Thermal transfer sheet, coating liquid for release layer, and method for producing thermal transfer sheet

ABSTRACT

To provide a coating liquid for release layer with which a release layer having a small variation in the performance difference can be stably formed, to provide a method for producing a thermal transfer sheet using this coating liquid for release layer, and to provide a thermal transfer sheet having stable releasability. A thermal transfer sheet having a substrate, a release layer provided on the substrate, and a transfer layer provided on the release layer, wherein the transfer layer is provided peelably from the release layer, and the release layer contains a silsesquioxane.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 16/768,365,filed May 29, 2020, which in turn is the National Stage entry ofInternational Application No. PCT/JP2019/003355, filed Jan. 31, 2019,which designated the United States, the entireties of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a thermal transfer sheet, a coatingliquid for release layer, and a method for producing a thermal transfersheet.

BACKGROUND OF THE INVENTION

In order to protect the surface of a transfer receiving article, forexample, in order to protect an image formed on a thermal transferimage-receiving sheet or an image formed on a card substrate, a thermaltransfer sheet (also referred to as a protective layer transfer sheet insome cases) comprising a transfer layer of a single-layer structure or alayered structure including a protective layer (also referred to as apeel layer in some cases) is used to transfer the transfer layer onto atransfer receiving article. Transfer receiving articles onto which atransfer layer has been transferred are used in a wide variety ofapplications such as ID cards, for example, identity cards, driver'slicenses, and membership cards. A thermal transfer sheet (also referredto as an intermediate transfer medium in some cases) provided with atransfer layer of a single-layer structure or a layered structureincluding a receiving layer and the like are also known. Transfer of thetransfer layer onto a transfer receiving article is conducted bysuperposing a thermal transfer sheet comprising the transfer layer on atransfer receiving article, applying energy on the thermal transfersheet to transfer the transfer layer onto the transfer receivingarticle, and then, peeling this transfer layer from the side of thesubstrate of the thermal transfer sheet.

Such a thermal transfer sheet is required to have good durability of thetransfer layer and a good peel property (also referred to asreleasability in some cases) when the transfer layer transferred ontothe transfer receiving article is peeled from the side of the substrateof the thermal transfer sheet.

Various studies have been conducted on durability of a transfer layer.For example, Patent Literature 1 suggests a thermal transfer sheet inwhich, as a transfer layer, a peel layer and a stress relaxation layerare provided on a substrate, and the peel layer is formed from anionizing radiation curable resin. According to the thermal transfersheet suggested in Patent Literature 1, it is supposed that highdurability can be imparted to the transfer layer by enhancing thehardness of the peel layer with the ionizing radiation curable resin.

However, the peel property of the transfer layer and the durability ofthe transfer layer are in a trade-off relationship. Thus, when thehardness of the transfer layer is enhanced in order to improve thedurability of the transfer layer, the peel property of the transferlayer tends to decrease. Particularly, when durability has been impartedto the transfer layer, the peel property at the peel head portion of thetransfer layer decreases. Thus, untransfer of the head portion of thetransfer layer (hereinafter referred to as head untransfer) is likely tooccur. In the head untransfer, the transfer layer, which originallyshould be transferred onto the transfer receiving article side and bepeeled from the side of the substrate of the thermal transfer sheet, isnot peeled from the side of the substrate and remains on the side of thethermal transfer sheet. Additionally, when the hardness of the transferlayer is lowered with focusing on the peel property of the transferlayer, the durability of the transfer layer tends to decrease. Notethat, when the peel property of the transfer layer decreases, untransferof the transfer layer, tailing, and the like are likely to occur.

As a thermal transfer sheet allowing the peel property of the transferlayer to be satisfactory, a thermal transfer sheet and the like alsohave been suggested in which a release layer is provided between thesubstrate and the transfer layer and the interface between the releaselayer and the transfer layer is used as a transfer interface. Note thatthe release layer referred to herein is a layer that remains on the sideof the substrate when the transfer layer is transferred.

Such a release layer is formed by dissolving or dispersing a componenthaving releasability in a suitable solvent to prepare a coating liquid,applying this coating liquid onto a substrate, followed by drying. Thecomponent for imparting releasability to the release layer issusceptible to the external environment when the coating liquidcontaining the component is applied and dried to form a release layer,and inherently includes a problem in that a variation in the performanceof the releasability is likely to occur, the releasability beingimparted to the release layer finally formed.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Laid-Open No. 7-186514

SUMMARY OF THE INVENTION Technical Problem

The present invention has been made in view of such situations, and thepresent invention aims principally to provide a thermal transfer sheetcapable of inhibiting occurrence of head untransfer when a transferlayer is transferred onto a transfer receiving article and capable ofimparting durability to a print obtained by transferring the transferlayer onto the transfer receiving article.

The present invention also aims principally to provide a coating liquidfor release layer with which a release layer having a small variation inthe performance difference can be stably formed, to provide a method forproducing a thermal transfer sheet using this coating liquid for releaselayer, and to provide a thermal transfer sheet having stablereleasability.

Solution to Problem

A thermal transfer sheet according to an embodiment of the presentdisclosure for solving the above problems has a substrate, a releaselayer provided on the substrate, and a transfer layer provided on therelease layer. The transfer layer is provided peelably from the releaselayer, and the release layer contains a silsesquioxane.

Additionally, a thermal transfer sheet according to an embodiment of thepresent disclosure for solving the above problems is a thermal transfersheet having a substrate, a release layer provided on the substrate, anda transfer layer provided on the release layer, wherein the transferlayer is provided peelably from the release layer, the release layercontains a silsesquioxane, the initial breakage peeling-off force whenthe transfer layer is peeled under conditions of a peeling-offtemperature of 20° C. or more and 40° C. or less and a peeling-off angleof 90° is 5 mN/m or less, and the initial breakage peeling-off forcewhen the transfer layer is peeled under conditions of a peeling-offtemperature of 20° C. or more and 70° C. or less and a peeling-off angleof 60° or more is 1.97 mN/m or less, and the scratch hardness (asapphire needle having a tip radius of 0.1 mm is used) when the facelocated on the side of the substrate of the transfer layer is measuredby a method in compliance with JIS-K-5600-5-5 is 200 g or more.

Additionally, a thermal transfer sheet according to an embodiment of thepresent disclosure for solving the above problems has a substrate, arelease layer provided on the substrate, and a transfer layer providedon the release layer. The transfer layer is provided peelably from therelease layer, and the release layer has a reaction product of asilsesquioxane having an epoxy group and a resin having a carboxylgroup.

Additionally, in the above thermal transfer sheet, the acid value of theresin having a carboxyl group may be 10 mgKOH/g or more.

Additionally, a coating liquid for release layer according to anembodiment of the present disclosure for solving the above problems is acoating liquid for release layer for forming a release layer of athermal transfer sheet, and contains a silsesquioxane.

Additionally, in the above coating liquid for release layer, the coatingliquid for release layer may further contain a resin having a carboxylgroup, and the silsesquioxane may be a silsesquioxane having an epoxygroup.

Additionally, in the above coating liquid for release layer, the acidvalue of the resin having a carboxyl group may be 10 mgKOH/g or more.

Additionally, a method for producing a thermal transfer sheet accordingto an embodiment of the present disclosure for solving the aboveproblems includes forming a release layer on a substrate and forming atransfer layer on the release layer, wherein forming a release layercomprises applying the above coating liquid for release layer, followedby drying.

Additionally, a thermal transfer sheet according to an embodiment of thepresent disclosure for solving the above problems is a thermal transfersheet having a substrate and a transfer layer provided on the substrate,wherein the initial breakage peeling-off force when the transfer layeris peeled under conditions of a peeling-off temperature of 20° C. ormore and 40° C. or less and a peeling-off angle of 90° is 5 mN/m orless, and the scratch hardness (a sapphire needle having a tip radius of0.1 mm is used) when the face located on the side of the substrate ofthe transfer layer is measured by a method in compliance withJIS-K-5600-5-5 is 200 g or more.

Additionally, a thermal transfer sheet according to an embodiment of thepresent disclosure for solving the above problems is a thermal transfersheet having a substrate and a transfer layer provided on the substrate,wherein the transfer layer has a single-layer structure consisting of aprotective layer or a layered structure including a protective layer,the protective layer contains a cured product of an active ray-curableresin, and the initial breakage peeling-off force when the transferlayer is peeled under conditions of a peeling-off temperature of 20° C.or more and 40° C. or less and a peeling-off angle of 90° is 5 mN/m orless.

Additionally, in the above thermal transfer sheet, a release layerdirectly contacting the transfer layer may be located between thesubstrate and the transfer layer, and the surface roughness (SRa) of thesurface located on the side of the transfer layer of the release layermay be 0.05 μm or more and 0.08 μm or less.

Additionally, in the above thermal transfer sheet, a release layerdirectly contacting the transfer layer may be located between thesubstrate and the transfer layer, the release layer may contain a fillerin an amount of 0.5% by mass or more and 1.5% by mass or less based onthe total mass of the release layer, and the volume average particlesize of the filler may be 2 μm or more and 5 μm or less.

Additionally, in the above thermal transfer sheet, a glossiness(measurement angle: 20°) when the surface of the transfer layer aftertransferred onto a transfer receiving article is measured by a method incompliance with JIS-Z-8741 may be 55% or more.

Additionally, a thermal transfer sheet according to an embodiment of thepresent disclosure for solving the above problems is a thermal transfersheet having a substrate and a transfer layer provided on the substrate,wherein the transfer layer has a single-layer structure or layeredstructure including a protective layer, the protective layer contains acured product of an active ray-curable resin, and the initial breakagepeeling-off force when the transfer layer is peeled under conditions ofa peeling-off temperature of 20° C. or more and 70° C. or less and apeeling-off angle of 600 or more is 1.97 mN/m or less.

In the above thermal transfer sheet, the scratch hardness (a sapphireneedle having a tip radius of 0.1 mm is used) when the face located onthe side of the substrate of the transfer layer is measured by a methodin compliance with JIS-K-5600-5-5 may be 200 g or more.

In the above thermal transfer sheet, the protective layer may furthercontain a first filler having a volume average particle size of 0.1 μmor more and 2 μm or less and a second filler having a volume averageparticle size of 40 nm or less.

Advantageous Effects of Invention

According to the thermal transfer sheet according to the embodiment ofthe present disclosure, it is possible to inhibit occurrence of headuntransfer when the transfer layer is transferred onto a transferreceiving article and impart durability to a print obtained bytransferring the transfer layer onto the transfer receiving article.Additionally, according to the coating liquid for release layeraccording to the embodiment of the present disclosure, it is possible tostably form a release layer having a small variation in the performancedifference. Additionally, according to the method for producing thethermal transfer sheet according to the embodiment of the presentdisclosure, it is possible to stably produce a thermal transfer sheethaving a small variation in the performance difference in releasability.Additionally, according to the thermal transfer sheet according to theembodiment of the present disclosure, it is possible to impart stablereleasability to the release layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are sectional schematic views illustrating one exampleof a thermal transfer sheet according to the embodiment of the presentdisclosure.

FIGS. 2A and 2B are sectional schematic views illustrating one exampleof a thermal transfer sheet according to the embodiment of the presentdisclosure.

FIGS. 3A and 3B are sectional schematic views illustrating one exampleof a thermal transfer sheet according to the embodiment of the presentdisclosure.

FIG. 4 is a schematic sectional view illustrating one example of a printobtained using the thermal transfer sheet according to the embodiment ofthe present disclosure.

FIG. 5 is a drawing illustrating the relationship between thestable-state peeling-off force and the initial breakage peeling-offforce.

FIGS. 6A and 6B are schematic views illustrating the relationshipbetween a winding diameter in a take-up roll and a peeling-off angle.

FIG. 7 is a schematic view illustrating one example of a method formeasuring the stable-state peeling-off force and the initial breakagepeeling-off force.

FIG. 8 is a sectional schematic view illustrating one example of athermal transfer sheet according to the embodiment of the presentdisclosure.

FIG. 9 is a sectional schematic view illustrating one example of thethermal transfer sheet according to the embodiment of the presentdisclosure.

FIGS. 10A and 10B are arrangement views illustrating the relationshipbetween a thermal transfer sheet and transparent double-sided tape usedfor measurement of the initial breakage peeling-off force.

FIGS. 11A and 11B are process drawings illustrating a method for peelinga transfer layer, and FIG. 11C is a view illustrating the tailing stateafter the transfer layer is peeled. FIGS. 11A to 11C are all schematicsectional views.

FIGS. 12A and 12B are one example of ²⁹Si NMR measurement results of arelease layer containing silsesquioxane.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention will be described with reference tothe drawings. The present invention may be embodied in many differentaspects and should not be construed as being limited to the descriptionof the exemplary embodiments below. In the drawings, components may beshown schematically regarding the width, thickness, shape and the like,compared with actual aspects, for the sake of clearer illustration. Theschematic drawings are merely examples and do not limit theinterpretations of the present invention in any way. In thespecification and the drawings, components that have substantially thesame functions as those described before with reference to a previousdrawing(s) bear the identical reference signs thereto, and detaileddescriptions thereof may be omitted. Unless otherwise specificallyspecified, each layer to be described in the following may contain oneof components to be exemplified for each layer or may contain two ormore of the components. Each layer may contain other components thanthose exemplified.

<<Thermal Transfer Sheet of First Embodiment>>

As shown in FIG. 1A, FIG. 2A, and FIG. 3, a thermal transfer sheetaccording to a first embodiment of the present disclosure (hereinafterreferred to as the thermal transfer sheet of the first embodiment of thepresent disclosure) has a substrate 1 and a transfer layer 10 providedpeelably from the substrate 1. The transfer layer 10 has a single-layerstructure or layered structure including a protective layer 3. Note thatFIG. 1A, FIG. 2A, and FIG. 3 are schematic sectional views illustratingone example of the thermal transfer sheet of the first embodiment of thepresent disclosure and that a thermal transfer sheet 100 of an aspectillustrated in FIG. 1A has a configuration in which the transfer layer10 of a single-layer structure consisting of the protective layer 3 isprovided on the substrate 1. The thermal transfer sheet 100 of an aspectillustrated in FIG. 2 has a release layer 2 provided between thesubstrate 1 and the transfer layer 10 in the thermal transfer sheet 100illustrated in FIG. 1A. In the thermal transfer sheet 100 of an aspectillustrated in FIG. 3A, the transfer layer 10 has a layered structure inwhich the protective layer 3 and an adhesive layer 5 are layered in thisorder from the side of the substrate 1, and in the thermal transfersheet 100 of an aspect illustrated in FIG. 3B, the transfer layer 10 hasa layered structure in which a peel layer 4, the protective layer 3, andthe adhesive layer 5 are layered in this order.

In describing advantages of the thermal transfer sheet of the firstembodiment of the present disclosure and a thermal transfer sheet of asecond embodiment described below, the relationship between the initialbreakage peeling-off force and occurrence of head untransfer will bedescribed.

The peeling-off force when a thermal transfer sheet in which a transferlayer is provided on a substrate is used to transfer the transfer layeronto a transfer receiving article, specifically, the peeling-off forcewhen a transfer layer is fused or bonded onto a transfer receivingarticle and this transfer layer is peeled from the side of the substrateexhibits behavior illustrated in FIG. 5, and the peeling-off force whenthe head part of the transfer layer (peel start portion) is peeled fromthe side of the substrate (initial breakage peeling-off force) exhibitsa larger value in comparison with the subsequent peeling-off force(stable-state peeling-off force). In other words, the head portion ofthe transfer layer, at which the peeling-off force increases, isunlikely to be accurately peeled from the side of the substrate. Thus,untransfer of the head portion (hereinafter referred to as headuntransfer) is likely to occur, wherein the transfer layer, whichoriginally should be transferred onto the side of the transfer receivingarticle and peeled from the side of the substrate of the thermaltransfer sheet, remains on the side of the thermal transfer sheetwithout being peeled from the side of the substrate. Furthermore, themagnitude of the initial breakage peeling-off force has a closerelevance to the strength of the transfer layer (the transfer layer maybe replaced by the protective layer). The higher the strength of thetransfer layer, the larger the initial breakage peeling-off force of thetransfer layer. In other words, in the case where, in a thermal transfersheet in which a transfer layer is provided on the substrate, thestrength of the transfer layer is enhanced in order to impart sufficientdurability to the transfer layer, head untransfer is likely to occuraccordingly.

The peel property when the transfer layer is peeled depends on thepeeling-off angle when the transfer layer is peeled from the side of thesubstrate of the thermal transfer sheet. In order to make the peelproperty of the transfer layer satisfactory, it is necessary to considerthe peel property of the transfer layer at a desired peeling-off angle.

FIGS. 6A and 6B are schematic views for describing the peeling-off angleof the thermal transfer sheet, each having a different initial positionof a take-up roll and a different take-up direction by the take-up roll.The schematic views of the figures have a feed roll that supplies athermal transfer sheet (a thermal transfer sheet before the transferlayer is transferred), a heating device that fuses the transfer layer ofthe thermal transfer sheet fed from the feed roll and a transferreceiving article to each other, a peeling device that peels thetransfer layer fused on the transfer receiving article from the side ofthe substrate of the thermal transfer sheet (e.g., a peel roll or peelplate), a take-up roll that takes up the thermal transfer sheet afterthe transfer layer is transferred (constituent members of the thermaltransfer sheet other than the transfer layer), a guide roll that guidesthe thermal transfer sheet fed from the feed roll to a conveyance path,and the like. In the aspect illustrated in the figures, peel by thepeeling device is completed to thereby provide a print in which thetransfer layer is transferred onto the transfer receiving article.

In FIGS. 6A and B, the smaller winding diameter denotes the windingdiameter of the take-up roll in the initial stage of peel of thetransfer layer, and the larger winding diameter denotes the windingdiameter of the take-up roll during progress of peel of the transferlayer. In the aspects illustrated in the figures, the peeling-off angleα1, which is the angle formed between the face of the transfer receivingarticle and the axis in the peel-off direction X1 during release (duringtransfer) is set to be 90°. In other words, the peeling-off angle α1 onthe smaller winding diameter of the take-up roll is set to be 90°. Notethat the peeling-off angle of 90° is a peeling-off angle at which thefoil cutting property when the transfer layer is peeled is satisfactoryand occurrence of tailing can be inhibited. The foil cutting property ofthe transfer layer referred to herein represents the degree ofinhibition of tailing when the transfer layer is transferred onto atransfer receiving article, and the case where the foil cutting propertyis satisfactory means that the occurrence of tailing can be inhibited.The tailing referred to herein means a phenomenon in which, when thetransfer layer is transferred onto a transfer receiving article, thetransfer layer is transferred so as to protrude to a non-transfer regionside from a boundary between a transfer region and the non-transferregion of the transfer layer as a start point.

The peeling-off angle when the transfer layer is peeled from the side ofthe substrate of the thermal transfer sheet is determined by the angleformed between the face of the transfer receiving article and the axisin the peel-off direction (tension direction) during peel. Here, in thecase where peel of the transfer layer (transfer of the transfer layer)is advanced from the side of the substrate of the thermal transfer sheetand the winding diameter of the take-up roll increases, the peel-offdirection shifts from the peel-off direction X1 at the initial stage,and accordingly, the peeling-off angle also varies. For example, in theaspect illustrated in FIG. 6A, in the case where take-up by the take-uproll is advanced and the winding diameter of the take-up roll increases(in the case the larger winding diameter is taken), the peeling-offangle α2, which is the angle formed between the face of the transferreceiving article and the peel-off direction X2 during peel becomeslarger than the peeling-off angle α1 at the initial stage of peel. Incontrast, in the aspect illustrated in FIG. 6B, in the case wheretake-up by the take-up roll is advanced and the winding diameter of thetake-up roll increases (in the case the larger winding diameter istaken), the peeling-off angle α2, which is the angle formed between theface of the transfer receiving article and the peel-off direction X2during peel becomes smaller than the peeling-off angle α1 at the initialstage of peel.

Accordingly, in order to inhibit occurrence of head untransfer, onlyconsidering the initial breakage peeling-off force at a desiredpeeling-off angle (in the aspect illustrated, a peeling-off angle of90°) is insufficient. In consideration of a variation in the peeling-offangle, it is necessary to set an initial breakage peeling-off forcecapable of inhibiting occurrence of head untransfer even at thepeeling-off angle after varied.

Note that, in FIGS. 6A and 6B, the relationship between the windingdiameter of the take-up roll that takes up the thermal transfer sheetafter the transfer layer is peeled therefrom and the peeling-off angleis described, but the variation in the peeling-off angle may occur dueto a factor other than this. For example, in the case where a peel rollis used as the peeling device, the peeling-off angle may depend on thesize of the peel roll diameter. Alternatively, in accordance with thewinding diameter of the feed roll and the tension applied on the thermaltransfer sheet during transferring the transfer layer, the peeling-offangle may vary. Alternatively, the peeling-off angle may vary due to afactor other than these. Such a variation in the peeling-off angle is inthe range of ±30° with respect to the reference axis, which is an axishaving a peeling-off angle of 90° with respect to the face of a transferreceiving article during peel.

The thermal transfer sheet 100 of the first embodiment of the presentdisclosure, in which this respect is considered, satisfies the followingconditions 1 and 2.

Condition 1: The transfer layer 10 has a single-layer structure orlayered structure including a protective layer 3, and the protectivelayer 3 contains a cured product of an active ray-curable resin.

Condition 2: The initial breakage peeling-off force when the transferlayer 10 is peeled under conditions of a peeling-off temperature of 20°C. or more and 70° C. or less and a peeling-off angle of 600 or more is1.97 mN/m or less.

According to the thermal transfer sheet 100 of the first embodiment ofthe present disclosure which satisfies the above conditions 1 and 2, itis possible to inhibit occurrence of head untransfer when the transferlayer 10 is peeled while imparting good durability to the transfer layer10 including the protective layer 3.

Note that the reason why the peeling-off angle is specified to 600 inthe condition 1 is that, in the case where the initial breakagepeeling-off force when the transfer layer 10 is peeled under conditionsof a peeling-off temperature of 20° C. or more and 70° C. or less and apeeling-off angle of 60° is 1.97 mN/m or less, even if the peeling-offangle is larger than 60°, the initial breakage peeling-off force is 1.97mN/m or less. Specifically, the reason why is that, if the aboveconditions are satisfied, the initial breakage peeling-off force is 1.97mN/m or less even at the upper limit peeling-off angle of 120°, at whicha variation in the peeling-off angle is anticipated. Accordingly, thethermal transfer sheet 100 of the first embodiment of the presentdisclosure is only required to satisfy the condition 1 and to have aninitial breakage peeling-off force when the transfer layer 10 is peeledunder conditions of a peeling-off temperature of 20° C. or more and 70°C. or less and a peeling-off angle of 60° of 1.97 mN/m or less. Also,the thermal transfer sheet 100 of the first embodiment of the presentdisclosure is only required to satisfy the condition 1 and to have aninitial breakage peeling-off force when the transfer layer 10 is peeledunder conditions of a peeling-off temperature of 20° C. or more and 70°C. or less and a peeling-off angle of 60° or more and 120° or less is1.97 mN/m or less.

Furthermore, according to the thermal transfer sheet 100 of the firstembodiment of the present disclosure which satisfies the aboveconditions 1 and 2, it is possible to inhibit occurrence of headuntransfer even in the case where the actual peeling-off angle variesfrom the specified peeling-off angle due to various factors exemplifiedabove. The above occurrence of head untransfer can be inhibited byeither peel modes: a hot peel mode and a cold peel mode. The hot peelmode referred to herein is a peel mode in which a thermal transfer sheetis applied with energy to melt or soften the transfer layer, and onlythe transfer layer transferred onto a transfer receiving article ispeeled from the thermal transfer sheet before this transfer layersolidifies, and the cold peel mode means a peel mode in which only thetransfer layer transferred onto a transfer receiving article is peeledfrom the thermal transfer sheet after the transfer layer has solidified.

(Method for Calculating Initial Breakage Peeling-Off Force 1)

The initial breakage peeling-off force in the thermal transfer sheet ofthe first embodiment of the present disclosure means a peeling-off forceto be calculated by the following method.

(A) A thermal transfer sheet to be measured is cut into a predeterminedwidth (hereinafter referred to as the width A). Note that the thermaltransfer sheet to be measured includes a substrate and a transfer layerprovided peelably from the substrate. Accordingly, the width of thetransfer layer after cut is also the width A.

(B) The cut thermal transfer sheet to be measured is attached onto thestage of a peel analyzer (VPA-3, Kyowa Interface Science Inc.).

(C-1) The peeling-off angle in the peel analyzer is set to 60°, and thetransfer layer is peeled from the side of the substrate of the thermaltransfer sheet under conditions of a stage temperature: 20° C.(peeling-off temperature: 20° C.) and a peel rate: 1464 mm/min. Thepeeling-off force in the range from the initial peeling-off portion asthe peel start position to a point 5 mm (5 mm exclusive) distant in thepeel-off direction is measured with the load cell measurement unitattached to the peel analyzer. Then, the initial breakage peeling-offforce at a peeling-off temperature of 20° C. can be calculated bydividing the peeling-off force having the maximum value among thepeeling-off forces measured (maximum peeling-off force in themeasurement range) by the length of the thermal transfer sheet in thewidth direction (width A).

(C-2) The initial breakage peeling-off force is calculated in the samemanner also at a peeling-off temperature: 70° C., at which the stagetemperature is adjusted to 70° C.

(C-3) The initial breakage peeling-off force is calculated in the samemanner as described above also at peeling-off angles of 90° and 120°.

In any of the above (C-1) to (C-3), in the case where the value of theinitial breakage peeling-off force is 1.97 mN/m or less, it can bedetermined that the initial breakage peeling-off force when the transferlayer is peeled satisfies the above condition 2.

In the thermal transfer sheet 100 of the first embodiment of the presentdisclosure, the initial breakage peeling-off force to be calculated bythe above method for calculating the initial breakage peeling-off forceis preferably 1.28 mN/m or less, more preferably 0.99 mN/m or less,under conditions of a peeling-off temperature of 20° C. or more and 40°C. or less and a peeling-off angle of 60°. According to the thermaltransfer sheet 100 of this aspect, it is possible to further lower thedependency on the peeling-off angle when the transfer layer 10 is peeledby the cold peel mode, and it is possible to further effectively inhibitoccurrence of head untransfer even in the case where the actualpeeling-off angle varies from the specified peeling-off angle.

Also, the thermal transfer sheet 100 of the first embodiment of thepresent disclosure satisfies the above conditions 1 and 2, and thestable-state peeling-off force when the transfer layer 10 is peeledunder conditions of a peeling-off temperature of 20° C. or more and 70°C. or less and a peeling-off angle of 600 or more is preferably 0.098mN/m or more and 1.97 mN/m or less, more preferably 0.098 mN/m or moreand 0.99 mN/m or less, particularly preferably 0.098 mN/m or more and0.5 mN/m or less. According to the thermal transfer sheet 100 of thisaspect, it is possible to have a further satisfactory foil cuttingproperty and transfer the transfer layer 10 onto a transfer receivingarticle while inhibiting head untransfer.

(Method for Calculating Stable-State Peeling-Off Force 1)

The stable-state peeling-off force referred to herein is a peeling-offforce to be measured in a measurement range from a point 5 mm distantfrom the initial peeling-off portion in the peel-off direction (seeFIGS. 5 and 7) to a point 15 mm distant from the initial peeling-offportion in the peel-off direction, that is, a measurement range from apoint 5 mm distant from the initial peeling-off portion in the peel-offdirection as the start point to a point 10 mm distant from this startpoint in the peel-off direction (peeling-off length: 10 mm), in themethod for calculating an initial breakage peeling-off force describedabove, and means a value obtained by dividing the peeling-off forcehaving the maximum value among the peeling-off forces measured (maximumpeeling-off force in the measurement range) by the length of the thermaltransfer sheet in the width direction (width A). In other words, in theabove Method for calculating initial breakage peeling-off force 1, thephrase “the peeling-off force in the range from the initial peeling-offportion to a point 5 mm (5 mm exclusive) distant in the peel-offdirection” may be replaced by “the peeling-off force in a range from apoint 5 mm distant from the initial peeling-off portion in the peel-offdirection to a point 15 mm distant from the initial peeling-off portionin the peel-off direction”.

Additionally, the thermal transfer sheet 100 of the first embodiment ofthe present disclosure satisfies the above conditions 1 and 2, and thescratch hardness (a sapphire needle having a tip radius of 0.1 mm isused) when the face located on the side of the substrate 1 of thetransfer layer 10 is measured by a method in compliance withJIS-K-5600-5-5 is preferably 200 g or more, more preferably 210 g ormore. Hereinbelow, the scratch hardness (a sapphire needle having a tipradius of 0.1 mm is used) when the face located on the side of thesubstrate 1 of the transfer layer 10 is measured by a method incompliance with JIS-K-5600-5-5 may be abbreviated as the scratchhardness of the face located on the side of the substrate 1 of thetransfer layer 10.

The scratch hardness of the face located on the side of the substrate 1of the transfer layer 10 can be measured by transferring the transferlayer 10 on a transfer receiving article. For measurement of the scratchhardness, a surface property tester (HEIDON TYPE: 14, Shinto ScientificCo., Ltd.) was used. The same applies to a thermal transfer sheet 100 ofa second embodiment of the present disclosure mentioned below.

Hereinbelow, each constituent of the thermal transfer sheet 100 of thefirst embodiment of the present disclosure will be concretely described.

(Substrate)

The substrate 1 has the transfer layer 10 constituting the thermaltransfer sheet 100 of the first embodiment of the present disclosure oran optional layer (e.g., a release layer 2) to be provided between thesubstrate 1 and the transfer layer 10. There is no particular limitationwith respect to the material of the substrate 1, but it is preferred forthe material to have heat resistance sufficient to endure the thermalenergy (e.g., a thermal head, heat roller, or hot stamp machine) whenthe transfer layer 10 is transferred (fused or bonded) onto a transferreceiving article and to have mechanical strength sufficient to supportthe transfer layer 10 and solvent resistance. Examples of the materialof the substrate 1 include polyesters such as polyethyleneterephthalate, polybutylene terephthalate, polyethylene naphthalate,polyethylene terephthalate—isophthalate copolymers, terephthalicacid—cyclohexanedimethanol—ethylene glycol copolymers, and polyethyleneterephthalate/polyethylene naphthalate coextruded films, polyamides suchas nylon 6 and nylon 66, polyolefins such as polyethylene,polypropylene, and polymethylpentene, vinyl resins such as polyvinylchloride, acryl resins such as polyacrylate, poly(meth)acrylate, andpolymethyl(meth)acrylate, imide resins such as polyimide and polyetherimide, engineering resins such as polyarylate, polysulfone, polyethersulfone, polyphenylene ether, polyphenylene sulfide (PPS), polyaramid,polyether ketone, polyether nitrile, polyether ether ketone, andpolyether sulfite, polycarbonate, polystyrenes such as polystyrene, highimpact polystyrene, acrylonitrile—styrene copolymers (AS resins), andacrylonitrile-butadiene—styrene copolymers (ABS resins), and cellulosessuch as cellophane, cellulose acetate, and nitrocellulose.

The substrate 1 may be a copolymer or a mixed product (including analloy) mainly based on the resins exemplified above, or a laminatecomposed of a plurality of layers. The substrate also may be a stretchedfilm or an unstretched film. For the purpose of improving the strength,films stretched in a uniaxial direction or biaxial direction arepreferably used. The substrate 1 can be used in the form of a film,sheet, or board composed of at least one layer of these resins. Amongthe substrates composed of the resins exemplified above, polyester filmssuch as polyethylene terephthalate and polyethylene naphthalate aresuitably used due to their excellent thermal resistance and mechanicalstrength. Among these, polyethylene terephthalate films are morepreferable.

For preventing blocking, it is possible to impart asperities to thesurface of the substrate 1 as required. Examples of procedures to formasperities on the surface of the substrate 1 include mattingagent-kneading processing, sand blast processing, hairline processing,matte coating processing, and chemical etching processing. The mattingagent-kneading processing is a processing method for forming a substratefrom a resin into which an inorganic material, or an organic material iskneaded. The matte coating processing is a processing method forimparting asperities to a substrate surface by coating the substratesurface with a coating agent containing an organic material or aninorganic material.

There is no particular limitation with respect to the thickness of thesubstrate 1, and the thickness is generally in the range of 0.5 μm ormore and 100 μm or less. The thickness is preferably 0.5 μm or more and50 μm or less, more preferably 4 μm or more and 25 μm or less. Byallowing the substrate to have a preferable thickness, it is possible tosufficiently transmit the energy to the side of the transfer layer 10when the transfer layer 10 is transferred from the thermal transfersheet 100, to thereby make a further improvement in the transferabilitywhen the transfer layer 10 is transferred. It is also possible toenhance the mechanical strength of the substrate 1 to therebysufficiently support the transfer layer 10.

The face located on the side of the transfer layer 10 of the substrate 1may be subjected to easily-adhesive treatment, in advance, such ascorona discharge treatment, plasma treatment, ozone treatment, flametreatment, primer (also referred to as an anchor coat, an adhesionpromoter, or an easy-adhesion agent) coating treatment, preheatingtreatment, dust removing treatment, vapor deposition treatment, alkalinetreatment, and addition of an antistatic layer. Additives such as afilling agent, a plasticizer, a colorant, and an antistatic agent may bealso added to the substrate 1 as required.

(Transfer Layer)

As shown in FIG. 1A, FIG. 2A, and FIG. 3, the transfer layer 10 isprovided directly or indirectly, via another layer, on the substrate 1.

(Protective Layer)

The transfer layer 10 has a single-layer structure consisting of aprotective layer 3 or a layered structure including the protective layer3. In the thermal transfer sheet 100 of the first embodiment of thepresent disclosure, the protective layer 3 constituting the transferlayer 10 contains a cured product of various curable resins (condition 1described above). In other words, the protective layer 3 contains aresin obtained by irradiating an active ray-curable resin with an activeray. The protective layer 3 contains a cured product of an activeray-curable resin.

The active ray-curable resin referred to herein means a precursor or acomposition before irradiated with an active ray. The active rayreferred to herein also means a radioactive ray which is allowed tochemically act on an active ray-curable resin to promote polymerization.Specific examples include visible light rays, ultraviolet rays, X rays,electron beams, α rays, β rays, and γ rays. Hereinbelow, the activeray-curable resin, which forms a cured product of an active ray-curableresin, will be described.

The active ray-curable resin as an example includes, as polymerizationcomponents, a composition and the like prepared by appropriately mixinga polymer, a prepolymer, an oligomer and/or a monomer having apolymerizable unsaturated bond such as a (meth)acryloyl group and a(meth)acryloyloxy group or an epoxy group in the molecule.

The active ray-curable resin as an example includes a polyfunctional(meth)acrylate as a polymerization component. As the polyfunctional(meth)acrylate, a polyfunctional (meth)acrylate having 5 or more and 15or less functional groups is preferable, and a polyfunctional(meth)acrylate having 6 or more and 15 or less functional groups is morepreferable. The active ray-curable resin as another example includes aurethane (meth)acrylate and preferably includes a polyfunctionalurethane (meth)acrylate, as a polymerization component. As thepolyfunctional urethane (meth)acrylate, a polyfunctional urethane(meth)acrylate having 5 or more and 15 or less functional groups ispreferable, and a polyfunctional urethane (meth)acrylate having 6 ormore and 15 or less functional groups is more preferable.

The (meth)acrylates referred to herein include acrylates andmethacrylates, (meth)acrylic acids include acrylic acid and methacrylicacid, and (meth)acrylic acid esters include acrylic acids ester andmethacrylic acid esters.

There is not particular limitation with respect to the content of thecured product of the active ray-curable resin based on the total mass ofthe protective layer 3. The content is preferably 5% by mass or more and80% by mass or less, more preferably 5% by mass or more and 70% by massor less, even more preferably 10% by mass or more and 50% by mass orless.

The protective layer 3 also preferably contains a cured product of aurethane (meth)acrylate, particularly, a cured product of apolyfunctional urethane (meth)acrylate in the content described above,as the cured product of the active ray-curable resin.

From the viewpoint of combining the solvent resistance and thebendability of the protective layer, the protective layer 3 preferablycontains a cured product of (i) a polyfunctional urethane (meth)acrylatehaving 5 or more and 15 or less functional groups, particularly 6 ormore and 15 or less functional groups and (ii) either one or both of apolyfunctional urethane (meth)acrylate having 2 or more and 4 or lessfunctional groups and a (meth)acrylate having 2 or more and 5 or lessfunctional groups. Alternatively, the protective layer 3 preferablycontains (iii) a cured product of a polyfunctional urethane(meth)acrylate having 5 or more and 15 or less functional groups,particularly 6 or more and 15 or less functional groups and (iv) eitherone or both of a cured product of a polyfunctional urethane(meth)acrylate having 2 or more and 4 or less functional groups and acured product of a (meth)acrylate having 2 or more and 5 or lessfunctional groups. The content of the component derived from (ii) thepolyfunctional urethane (meth)acrylate having 2 or more and 4 or lessfunctional groups and the (meth)acrylate having 2 or more and 5 or lessfunctional groups described above is preferably 5% by mass or more and80% by mass or less, more preferably 10% by mass or more and 70% by massor less, based on the total mass of the protective layer 3. The sameapplies to (iv) the cured product of a polyfunctional urethane(meth)acrylate having 2 or more and 4 or less functional groups and thecured product of a (meth)acrylate having 2 or more and 5 or lessfunctional groups described above.

Additionally, as the polyfunctional urethane (meth)acrylate as apolymerization component, one having a weight average molecular weightof 400 or more and 20000 or less is preferable, and one having a weightaverage molecular weight of 500 or more and 10000 or less is morepreferable. By using a urethane (meth)acrylate having a weight averagemolecular weight within the above preferable range as the urethane(meth)acrylate, it is possible to further improve the abrasionresistance and foil cutting property of the protective layer 3. For asimilar reason, the weight average molecular weight of the(meth)acrylate having 2 or more and 5 or less functional groups ispreferably 200 or more and 5000 or less. Note that the “weight averagemolecular weight” herein means a value measured by gel permeationchromatography using polystyrene as the standard substance and can bemeasured by a method in compliance with JIS-K-7252-1 (2008).

The active ray-curable resin as an example also includes an unsaturatedbond-containing (meth)acrylate copolymer (hereinafter also referred toas an unsaturated bond-containing acrylic copolymer in some cases) as apolymerization component. Examples of the unsaturated bond-containing(meth)acrylate copolymer include polyester (meth)acrylate, epoxy(meth)acrylate, melamine (meth)acrylate, and triazine (meth)acrylate.

Additionally, as the unsaturated bond-containing acrylic copolymer as apolymerization component, one having an acid value of 5 mgKOH/g or moreand 500 mgKOH/g or less is preferable, and one having an acid value of10 mgKOH/g or more and 150 mgKOH/g or less is more preferable. By usingan unsaturated bond-containing acrylic copolymer having an acid valuewithin the above preferable range as the unsaturated bond-containingacrylic copolymer, it is possible to enhance the surface strength of theprotective layer 3. The acid value of the polymer can be appropriatelyadjusted by adjusting the ratio of monomer components constituting thepolymer.

Additionally, as the unsaturated bond-containing acrylic copolymer, onehaving a weight average molecular weight of 3000 or more and 100000 orless is preferable, and one having a weight average molecular weight of10000 or more and 80000 or less is more preferable. By using anunsaturated bond-containing acrylic copolymer having a weight averagemolecular weight within the above preferable range as the unsaturatedbond-containing acrylic copolymer, it is possible to impart higherchemical durability such as thermal resistance and chemical resistanceand physical durability such as scratch strength to the protective layer3. It is also possible to inhibit gelling reaction during storage of acoating liquid for protective layer for forming a protective layer andto improve the storage stability of the coating liquid for protectivelayer.

The unsaturated bond-containing acrylic copolymer is preferablycontained in the range of 10% by mass or more and 80% by mass or less,more preferably contained in the range of 20% by mass or more and 70% bymass or less, even more preferably contained in the range of 20% by massor more and 50% by mass or less, in the active ray-curable resin.

The active ray-curable resin may also include, as a polymerizationcomponent, an oligomer and/or monomer of (meth)acrylic acid, styrene,vinyl acetate, hydroxyethyl vinyl ether, ethylene glycol divinyl ether,pentaerythritol trivinyl ether, (meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-vinylformamide, acrylonitrile, or the like, inaddition to the unsaturated bond-containing acrylic copolymer. Theactive ray-curable resin may also include a prepolymer, oligomer and/ormonomer as follows.

Examples of the prepolymer include polyester (meth)acrylates obtained byintroducing (meth)acrylic acid into a polyester obtained by bonding apolybasic acid such as adipic acid, trimellitic acid, maleic acid,phthalic acid, terephthalic acid, himic acid, malonic acid, succinicacid, glutaric acid, itaconic acid, pyromellitic acid, fumaric acid,glutaric acid, pimelic acid, sebacic acid, dodecanoic acid, ortetrahydrophthalic acid with a polyhydric alcohol such as ethyleneglycol, propylene glycol, diethylene glycol, propylene oxide,1,4-butanediol, triethylene glycol, tetraethylene glycol, polyethyleneglycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol,1,6-hexanediol, or 1,2,6-hexanetriol; epoxy (meth)acrylates obtained byintroducing (meth)acrylic acid into an epoxy resin such as bisphenolA—epichlorohydrin—(meth)acrylic acid and phenolnovolac-epichlorohydrin—(meth)acrylic acid; urethane(meth)acrylatesobtained by introducing (meth)acrylic acid into polyurethane such asethylene glycol—adipic acid-tolylene diisocyanate—2-hydroxyethylacrylate, polyethylene glycol—tolylene diisocyanate—2-hydroxyethylacrylate, hydroxyethyl phthalyl methacrylate—xylene diisocyanate,1,2-polybutadiene glycol—tolylene diisocyanate—2-hydroxyethyl acrylate,and trimethylolpropane—propylene glycol—tolylenediisocyanate—2-hydroxyethyl acrylate; silicone resin acrylates such aspolysiloxane (meth)acrylate and polysiloxane—diisocyanate—2-hydroxyethyl(meth)acrylate, and additionally, alkyd-modified (meth)acrylatesobtained by introducing a (meth)acryloyl group into an oil-modifiedalkyd resin, and spiran resin acrylates.

Examples of the monomer or oligomer include monofunctional acrylic acidesters such as 2-ethylhexyl acrylate, 2-hydroxypropyl acrylate, glycerolacrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate,nonylphenoxyethyl acrylate, tetrahydrofurfuryloxyethyl acrylate,tetrahydrofurfuryloxyhexanolide acrylate, acrylates of ε-caprolactoneadducts of 1,3-dioxane alcohol, and 1,3-dioxolane acrylate.

Examples thereof include bifunctional acrylic acid esters such asethylene glycol diacrylate, triethylene glycol diacrylate,pentaerythritol diacrylate, hydroquinone diacrylate, resorcindiacrylate, hexanediol diacrylate, neopentyl glycol diacrylate,tripropylene glycol diacrylate, diacrylate of neopentyl glycolhydroxypivalate, diacrylate of neopentyl glycol adipate, diacrylates ofε-caprolactone adducts of neopentyl hydroxypivalate glycol,2-(2-hydroxy-1,1-dimethylethyl)-5-hydroxymethyl-5-ethyl-1,3-dioxanediacrylate, tricyclodecanedimethylol acrylate, ε-caprolactone adducts oftricyclodecanedimethylol acrylate, and diacrylate of diglycidyl ether of1,6-hexanediol; polyfunctional acrylic acid esters such astrimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate,trimethylolethane triacrylate, pentaerythritol triacrylate,pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate,dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate,ε-caprolactone adducts of dipentaerythritol hexaacrylate, pyrogalloltriacrylate, propionic acid—dipentaerythritol triacrylate, propionicacid—dipentaerythritol tetraacrylate, and hydroxypivalylaldehyde-modified dimethylolpropane triacrylate; phosphazene monomers,triethylene glycol, EO-modified isocyanurate diacrylate, EO-modifiedisocyanurate triacrylate, dimethyloltricyclodecane diacrylate,trimethylolpropane acrylic acid benzoic acid esters, and alkyleneglycol-type acrylic acid-modified and urethane-modified acrylates.Methacrylic acid, itaconic acid, crotonic acid, maleic acid esters, orthe like obtained by replacing the acrylate by methacrylate, itaconate,crotonate, or maleate also may be used.

The protective layer 3 may contain one cured product of the activeray-cured resin singly or may contain two or more cured products of theactive ray-cured resin. The protective layer 3 may contain another resintogether with the cured product of the active ray-curable resin. Anotherresin may be a cured resin cured with a curing agent or the like or maybe an uncured resin. The same applies to a protective layer 3 in thetransfer layer 10 of the second embodiment mentioned below.

The protective layer 3 of a preferable aspect contains a filler having avolume average particle size of 0.1 μm or more and 2 μm or less.Hereinbelow, the filler having a volume average particle size of 0.1 μmor more and 2 μm or less is referred to as a first filler. The volumeaverage particle size of the filler referred to herein is a valuedetermined by measurement using a grain size distribution/particle sizedistribution analyzer (Nanotrac grain size distribution analyzer,Nikkiso Co., Ltd.) in compliance with JIS-Z-8819-2 (2001).

According to the protective layer 3 containing the first filler, it ispossible to inhibit occurrence of head untransfer more effectively.

There is no particular limitation with respect to the component of thefirst filler, and examples of the filler include organic fillers,inorganic fillers, and organic-inorganic hybrid type fillers. The fillermay be a powder or a sol-type one, but a powder filler is preferablyused because of its wide solvent-selectivity when a coating liquid forprotective layer is prepared.

Examples of the powder organic filler can include acryl particles suchas uncrosslinked acryl particles and crosslinked acryl particles,polyamide particles, fluorine particles, polyethylene wax, and siliconeparticles. Examples of the powder inorganic filler include aluminumparticles, zirconia particles, calcium carbonate particles, silicaparticles, and metal oxide particles such as titanium oxide and zincoxide particles. Examples of the filler of organic-inorganic hybrid typeinclude ones prepared by hybridizing an acryl resin with silicaparticles. Additionally, examples of the sol-type filler include silicasol-type and organosol-type fillers. It is also possible to useparticles surface-treated using a silane coupling agent such asγ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, orthe like. One of these fillers may be used singly, or two or more ofthese may be used in combination. Among these, silica particles aresuitable.

There is also no limitation with respect to the shape of the firstfiller, and examples of the shape include spherical, polygonal,acicular, feathery, and amorphous shapes.

The content of the first filler is preferably 2% by mass or more and 30%by mass or less, more preferably 6% by mass or more and 30% by mass orless, even more preferably 6% by mass or more and 20% by mass or less,particularly preferably 8% by mass or more and 20% by mass or less,based on the total mass of the protective layer 3. It is possible toinhibit occurrence of head untransfer further effectively by setting thecontent of the first filler to the preferable content described above.It is also possible to make the foil cutting property of the transferlayer further satisfactory.

The protective layer 3 of the preferable aspect also contains a fillerhaving a volume average particle size of 40 nm or less. Hereinbelow, thefiller having a volume average particle size of 40 nm or less isreferred to as a second filler. There is no limitation with respect tothe lower limit of the volume average particle size of the secondfiller, and example is of the order of 1 nm.

According to the protective layer 3 containing the second filler, it ispossible to make the durability of the transfer layer 10 furthersatisfactory. The protective layer 3 of a particularly preferable aspectcontains the first filler and the second filler.

The second filler is different from the first filler described above inthat the volume average particle size is 40 nm or less, and except forthis difference, it is possible to appropriately select and use thefirst filler components described above.

The content of the second filler is preferably 5% by mass or more and60% by mass or less, more preferably 10% by mass or more and 50% by massor less, still more preferably 20% by mass or more and 40% by mass orless, based on the total mass of the protective layer 3. It is possibleto make the durability of the protective layer 3 further satisfactory bysetting the content of the second filler to the above preferablecontent. Accordingly, it is possible to impart sufficient durability toa print to be obtained by transferring the transfer layer 10 includingthe protective layer 3 onto a transfer receiving article.

The protective layer 3 may contain one filler or two or more fillers, asthe first filler and the second filler. Alternatively, the protectivelayer 3 may contain a filler having a volume average particle sizedifferent from that of the first filler and the second filler.

There is no particular limitation with respect to the thickness of theprotective layer 3, and the thickness is preferably 1 μm or more and 15μm or less, preferably 2 μm or more and 6 μm or less. It is possible tomake the foil cutting property satisfactory by setting the thickness ofthe protective layer 3 within this range. It is also possible to inhibitoccurrence of defective transfer such as picking and chipping duringtransfer of the transfer layer 10.

There is not particular limitation with respect to the method forforming the protective layer 3, and the protective layer 3 can be formedby preparing a coating liquid for protective layer containing an activeray-curable resin and optional components, applying this coating liquidonto the substrate 1 or an optional layer provided on the substrate 1(e.g., the release layer 2), drying the liquid to form a coating film ofa protective layer, and irradiating this coating film with an active rayto crosslink and cure the polymerization components such as the abovepolymerizable copolymer. When ultraviolet irradiation is applied asactive ray irradiation, conventionally known ultraviolet irradiationapparatuses can be used. For example, various apparatuses such as highpressure mercury lamps, low pressure mercury lamps, carbon arcs, xenonarcs, metal halide lamps, non-electrode ultraviolet lamps, and LEDs canbe used without limitation. Alternatively, when an electron beam isapplied as active ray irradiation, a high energy-type electron beamirradiation apparatus that applies an electronic beam at an energy of100 keV or more and 300 keV or less, a low energy-type electron beamirradiation apparatus that applies an electronic beam at an energy of100 keV or less, or the like can be used. In terms of the irradiationmode, either of a scanning-type irradiation apparatus or a curtain-typeirradiation apparatus may be used. There is no particular limitation onthe method for applying the coating liquid for protective layer, and anyconventionally known application method can be appropriately selectedand used. Examples of the application method include a gravure printingmethod, a screen printing method, and a reverse roll coating methodusing a gravure printing plate. Application methods other than thesemethods also may be used. The same applies to methods for applyingvarious coating liquids described below. Examples of the drying methodinclude methods of removing the solvent by hot air drying.

(Adhesive Layer)

As shown in FIGS. 3A and 3B, the transfer layer 10 may have a layeredstructure in which an adhesive layer 5 is provided on the protectivelayer 3. According to the thermal transfer sheet 100 of this aspect, itis possible to make adhesion between the transfer layer 10 and atransfer receiving article 50 satisfactory when the transfer layer 10 istransferred onto the transfer receiving article 50, due to the presenceof the adhesive layer 5. FIG. 3 is a schematic sectional viewillustrating one example of the thermal transfer sheet of the firstembodiment of the present disclosure. In each view, an optional layersuch as a primer layer or the like also may be located between thelayers constituting the transfer layer 10.

The adhesive layer contains a component having an adhesive property.Examples of the component having an adhesive property include ionomerresins, acid-modified polyolefins, ethylene—(meta)acrylic acidcopolymers such as ethylene—(meth)ethylacrylate copolymers, acrylic acidester copolymers such as ethylene—(meth)acrylic acid ester copolymers,polyurethanes, polyolefins such as α-olefin—maleic anhydride,polyesters, acryl resins, epoxy resins, urea resins, melamine resins,phenol resins, vinyl acetate, vinyl resins such as vinyl chloride—vinylacetate copolymers, cyano acrylate, acrylic acid esters, maleic acidresins, polyvinyl butyral, alkyd resins, polyethylene oxides, phenolresins, urea resins, melamine—alkyd resins, cellulose resins,polyurethane, polyvinyl ether, silicone resins, and rubber-type resins.It is also possible to use products obtained by curing these resins witha curing agent. As the curing agent, isocyanate compounds are common,but aliphatic amines, alicyclic amines, aromatic amines, acidanhydrides, and the like can be used.

Among the components exemplified above, vinyl resins, acryl resins,polyvinyl butyral, polyesters, ethylene—(meth)acrylic acid copolymers,and acrylic acid ester copolymers are preferable.

Additionally, a function as a receiving layer may be imparted to theadhesive layer 5. In the case where the adhesive layer 5 has a functionof a receiving layer, a print having a thermal transfer image can beobtained by forming a thermal transfer image on the adhesive layer 5having a function of a receiving layer using a thermal transfer sheetincluding a die layer and transferring the transfer layer 10 includingthe adhesive layer 5 on which the thermal transfer image has been formedonto a transfer receiving article. In the case where the adhesive layer5 functions as a receiving layer, it is possible to use conventionallyknown resin materials which can easily receive thermally-transferablecolorants such as subliming dyes or thermally-fusible inks. Examples ofthe materials include polyolefins such as polypropylene, halogenatedresins such as polyvinyl chloride or polyvinylidene chloride, vinylresins such as polyvinyl acetate, vinyl chloride—vinyl acetatecopolymers, ethylene—vinyl acetate copolymers, or polyacrylic acidesters, polyesters such as polyethylene terephthalate or polybutyleneterephthalate, copolymers of an olefin such as polystyrene, polyamide,ethylene, or propylene and another vinyl polymer, ionomers, or celluloseresins such as cellulose diacetate, and polycarbonate. Among these, avinyl chloride—vinyl acetate copolymer or polyvinyl chloride ispreferable, and a vinyl chloride—vinyl acetate copolymer is morepreferable.

There is no particular limitation with respect to the method for formingthe adhesive layer 5, and the adhesive layer 5 can be formed bydispersing or dissolving a component having an adhesive property andvarious additives to be added as required into a suitable solvent toprepare a coating liquid for adhesive layer, applying this coatingliquid onto the protective layer 3, followed by drying. The thickness ofthe adhesive layer is preferably 0.1 μm or more and 10 μm or less, morepreferably 0.5 μm or more and 10 μm or less, even more preferably 0.8 μmor more and 3 μm or less, particularly preferably 0.3 μm or more and 2μm or less.

(Peel Layer)

As shown in FIG. 3B, among the layers constituting the transfer layer10, the peel layer 4 may be located nearest from the side of thesubstrate 1. It is possible to make the transferability of the transferlayer 10 satisfactory by locating the peel layer 4 on the transferinterface of the transfer layer 10.

Examples of the components of the peel layer 4 include ethylene—vinylacetate copolymers, vinyl chloride—vinyl acetate copolymers, maleicacid-modified vinyl chloride—vinyl acetate copolymers, polyamides,polyesters, polyethylene, ethylene—isobutyl acrylate copolymers,polyvinyl butyral, polyvinyl acetate and copolymers thereof, ionomerresins, acid-modified polyolefins, acryl resins, (meth)acryl resins,(meth)acrylic acid ester resins, ethylene—(meth)acrylic acid copolymers,ethylene—(meth)acrylic acid ester copolymers, polymethyl (meth)acrylate,cellulose resins, polyvinyl ethers, polyurethanes, polycarbonate,polypropylene, epoxy resins, phenol resins, vinyl resins, maleic acidresins, alkyd resins, polyethylene oxides, urea resins, melamine resins,melamine—alkyd resins, silicone resins, rubber-type resins,styrene—butadiene—styrene block copolymers (SBS),styrene—isoprene—styrene block copolymers (SIS),styrene—ethylene—butylene—styrene block copolymers (SEBS), andstyrene—ethylene—propylene—styrene block copolymers (SEPS). For the peellayer 4, one of these components may be used singly, or two or more ofthese may be used in combination.

There is no particular limitation with respect to the method for formingthe peel layer 4, and the peel layer 4 may be formed by dispersing ordissolving the components exemplified above and additives to be added asrequired into a suitable solvent to prepare a coating liquid for peellayer, applying this coating liquid onto the substrate 1 or an optionallayer provided on the substrate 1, followed by drying. There is notparticular limitation with respect to the thickness of the peel layer 4,and the thickness is preferably 1 μm or more and 15 μm or less.

(Release Layer)

As shown in FIG. 2, the release layer 2 may be provided between thesubstrate 1 and the transfer layer 10. The release layer is an optionalconstituent in the transfer sheet 100 of the first embodiment of thepresent disclosure, is a layer not constituting the transfer layer 10,and is a layer that remains on the side of the substrate 1 when thetransfer layer 10 is transferred onto the transfer receiving article. Itis possible to make the transferability of the transfer layer 10satisfactory by providing the release layer between the substrate 1 andthe transfer layer 10.

Examples of the components of the release layer 2 include waxes,silicone wax, silicone resins, silicone-modified resins, fluorineresins, fluorine-modified resins, polyvinyl alcohol, acryl resins,thermally crosslinkable epoxy—amino resins, thermally crosslinkablealkyd—amino resins, and polyesters. The release layer may be made fromone resin or may be made from two or more resins. The release layer maybe formed by using a crosslinking agent such as an isocyanate compoundand a catalyst such as a tin-based catalyst and an aluminum-basedcatalyst, in addition to the resin having releasability.

Note that the thermal transfer sheet 100 of the first embodiment of thepresent disclosure satisfies the above condition 2 and accordingly, thestable-state peeling-off force of the transfer layer 10 tends todecrease. Thus, in the case where the release layer 2 is providedbetween the substrate 1 and the transfer layer 10, the release layer 2preferably contains polyester. According to the thermal transfer sheetincluding the release layer 2 containing polyester of the firstembodiment of the present disclosure, it is possible to make thestable-state peeling-off force when the transfer layer is transferredsatisfactory. Thereby, it is possible to make the foil cutting propertyof the transfer layer more satisfactory to thereby inhibit occurrence oftailing more effectively. The content of the polyester is preferably0.5% by mass or more and 5% by mass or less based on the total mass ofthe release layer 2.

The thickness of the release layer is generally 0.2 μm or more and 5 μmor less. As the method for forming the release layer, the release layercan be formed by dispersing or dissolving the above components into asuitable solvent to prepare a coating liquid for release layer, applyingthis coating liquid onto the substrate 1 or an optional layer providedon the substrate 1, followed by drying.

Then, devices for allowing the transfer layer 10 to include theprotective layer 3 containing a cured product of the active ray-curableresin and to satisfy the above condition 2 will be described withreference to one example. Note that the thermal transfer sheet 100 ofthe first embodiment of the present disclosure is not limited to onesproduced by devices exemplified below and is only required to satisfythe above conditions 1 and 2.

(First Device)

A first device is a device that causes the protective layer 3 to containa filler having a predetermined volume average particle size. A specificexample includes a device that causes the protective layer 3 to containa filler having a volume average particle size of 0.1 μm or more.

(Second Device)

A second device is a device that adjusts the peak illuminance andaccumulated exposure of an active ray when a cured product of the activeray-curable resin is obtained, in other words, when a coating liquid forprotective layer containing the active ray-curable resin is applied anddried, and this coating film is irradiated with an active ray to obtaina cured product of the active ray-curable resin. Specific examplesinclude (i) a device that provides a protective layer by irradiating anactive ray-curable resin with an active ray under conditions of a peakilluminance of 1000 mW/cm² or less and an accumulated exposure of 400mJ/cm² or less, and (ii) a device that provides a protective layer byirradiating an active ray-curable resin with an active ray twice ormore, wherein the first active ray irradiation is conducted underconditions of a peak illuminance of 1000 mW/cm² or less, and anaccumulated exposure of 200 mJ/cm² or less, and the second and lateractive ray irradiations are conducted under conditions of a peakilluminance of more than 1000 mW/cm² and an accumulated exposure of 200mJ/cm² or less, such that the total of the accumulated exposure of theirradiations adds up to 400 mJ/cm². Alternatively, the second device canbe combined with the above first device to satisfy the above secondcondition.

(Third Device)

A third device is a device that provides a release layer between thesubstrate 1 and the transfer layer 10. Examples of the third deviceinclude a device that causes the release layer to contain a siliconeresin and a device that causes the release layer to contain a filler.The third device is one example of an auxiliary device for satisfyingthe above condition 2. The third device is preferably conducted incombination with the above first device or second device.

The silicone resin referred to herein means a compound having a siloxanebond in the molecular structure, and the concept thereof includes any ofunmodified silicone resins, modified silicone resins, andsilicone-modified resins. A silicone-modified resin can be prepared bycopolymerization of a polysiloxane group-containing vinyl monomer with avinyl monomer of another type, reaction of a thermoplastic resin with areactive silicone resin, or the like.

Examples of the silicone-modified resin can include silicone-modifiedresins prepared by a method of block copolymerizing a thermoplasticresin with a polysiloxane group-containing vinyl monomer, by a method ofgraft copolymerizing a thermoplastic resin with a polysiloxanegroup-containing vinyl monomer, or by a method of allowing athermoplastic resin react with a reactive silicone resin. Examples ofthe thermoplastic resin constituting the silicone-modified resin caninclude acryl resins, polyurethane, polyester, epoxy resins, polyvinylacetals, polycarbonate, and polyimides.

The reactive silicone resin is a compound that has a polysiloxanestructure as the main chain and also has a reactive functional group(s)that react(s) with a functional group of the thermoplastic resin at oneend or both ends. Examples of the above reactive functional group caninclude an amino group, a hydroxyl group, an epoxy group, a vinyl group,and a carboxyl group.

Alternatively, the first device to the third device may be appropriatelycombined.

<<Thermal Transfer Sheet of Second Embodiment>>

As shown in FIG. 1, FIG. 2, and FIG. 3, a thermal transfer sheetaccording to a second embodiment of the present disclosure (hereinafterreferred to as the thermal transfer sheet of the second embodiment ofthe present disclosure) has a substrate 1 and a transfer layer 10provided peelably from the substrate 1. The transfer layer 10 may have asingle-layer structure or may have a layered structure in which two ormore layers are layered. Note that FIG. 1, FIG. 2, and FIG. 3 areschematic sectional views illustrating one example of the thermaltransfer sheet of the second embodiment of the present disclosure, and athermal transfer sheet 100 of an aspect illustrated in FIG. 1B has aconfiguration in which the transfer layer 10 is provided on thesubstrate 1. The thermal transfer sheet 100 of an aspect illustrated inFIG. 2B has a configuration in which a release layer 2 is provided onthe substrate 1 and the transfer layer 10 is provided on the releaselayer 2.

The thermal transfer sheet 100 of the second embodiment of the presentdisclosure having the configuration described above satisfies thefollowing conditions 3 and 4.

(Condition 3): The initial breakage peeling-off force when the transferlayer 10 is peeled under conditions of a peeling-off temperature of 20°C. or more and 40° C. or less and a peeling-off angle of 90° is 5 mN/mor less.

(Condition 4): The scratch hardness (a sapphire needle having a tipradius of 0.1 mm is used) when the face located on the side of thesubstrate 1 of the transfer layer 10 is measured by a method incompliance with JIS-K-5600-5-5 is 200 g or more.

According to the thermal transfer sheet 100 of the second embodiment ofthe present disclosure satisfying the above condition 3, it is possibleto inhibit head untransfer when the transfer layer 10 is peeled. Therelationship between the head untransfer and the initial breakagepeeling-off force is as mentioned above.

Additionally, according to the thermal transfer sheet 100 of the secondembodiment of the present disclosure satisfying the above condition 4,it is possible to impart sufficient durability to the transfer layer 10.Accordingly, it is possible to impart high durability to a print 60obtained by transferring the transfer layer 10 onto a transfer receivingarticle (see FIG. 4). Note that the face located on the side of thesubstrate 1 of the transfer layer 10 will be the outermost surface whenthe transfer layer 10 is transferred onto the transfer receiving article50.

According to the thermal transfer sheet 100 of the second embodiment ofthe present disclosure satisfying the above conditions 3 and 4, it ispossible to transfer the transfer layer 10 having excellent durability,in a state where occurrence of head untransfer is inhibited, onto thetransfer receiving article 50.

That is, in the thermal transfer sheet 100 of the second embodiment ofthe present disclosure, which has a configuration that satisfies theconditions 3 and 4, a combination of improvement of durability of thetransfer layer and inhibition of head untransfer when the transfer layeris transferred is achieved.

Note that this also applies to a transfer layer 10 in which the transferlayer 10 satisfying the above condition 4 is replaced by a transferlayer 10 having the single-layer structure consisting of the protectivelayer 3 (see FIG. 1A) or the layered structure having the protectivelayer 3 (see FIGS. 3A and 3B) and the protective layer 3 is caused tocontain a cured product of an active ray-curable resin. Hereinbelow,each constituent of the thermal transfer sheet 100 of the secondembodiment of the present disclosure will be concretely described, withemphasis on differences from each constituent of the thermal transfersheet 100 of the first embodiment.

(Substrate)

The substrate 1 has the transfer layer 10 constituting the thermaltransfer sheet 100 of the second embodiment of the present disclosure oran optional layer (e.g., a release layer 2) provided between thesubstrate 1 and the transfer layer 10. There is no limitation withrespect to the substrate, and the substrate described in the thermaltransfer sheet 100 of the first embodiment described above can beappropriately selected and used.

Hereinbelow, the transfer layer 10 provided on the substrate 1 will bedescribed with reference to the transfer layer of a first aspect and thetransfer layer of a second aspect as examples. Hereinbelow, thereference to the transfer layer may include both the transfer layer ofthe first aspect and the transfer layer of the second aspect.

(Transfer Layer of First Aspect)

A transfer layer 10 of the first aspect has a scratch hardness (asapphire needle having a tip radius of 0.1 mm is used) of 200 g or morewhen the face located on the side of the substrate 1 of the transferlayer 10 is measured by a method in compliance with JIS-K-5600-5-5. Thatis, the transfer layer 10 of the first aspect satisfies the abovecondition 4. A preferable transfer layer 10 of the first aspect has ascratch hardness of 250 g or more of the face located on the side of thesubstrate 1 of the transfer layer 10.

The transfer layer 10 of the first aspect may have a single-layerstructure or may have a layered structure. In the case where thetransfer layer 10 of the first aspect has a layered structure, among thelayers constituting the transfer layer 10, the layer of which surfacehas a scratch hardness of 200 g or more is located nearest from the sideof the substrate 1. Hereinbelow, the reference to a base layer means thelayer located nearest from the side of the substrate 1 among the layersconstituting the transfer layer 10. Note that, in the case where thetransfer layer 10 of the first aspect has a single-layer structure, thetransfer layer 10 itself will be the base layer.

In the transfer layer 10 of the first aspect as one example, the baselayer contains a cured product of various curable resins. According tothe transfer layer 10 of the first aspect in which the base layercontains a cured product of various curable resins, it is possible toadjust the scratch hardness of the face located on the side of thesubstrate 1 of the transfer layer 10 to 200 g or more by appropriatelysetting the content of the cured product of these various curable resinsand the thickness of the base layer. Examples of the cured product ofvarious curable resins can include cured products of a thermoplasticresin and cured products of an active ray-curable resin. The base layermay contain one of the cured products of these or may contain two ormore cured products of these.

Examples of the thermoplastic resin forming cured products of thethermoplastic resin can include polyesters, polyacrylic acid esters,polyvinyl acetate, acryl—styrene copolymers, polyurethane, polyolefinssuch as polyethylene and polypropylene, polystyrene, polyvinyl chloride,polyethers, polyamides, polyimides, polyamideimides, polycarbonate,polyacrylamide, polyvinyl chloride, polyvinyl acetals such as polyvinylbutyral and polyvinyl acetoacetal, and silicone-modified forms of these.The transfer layer 10 of the first aspect may contain one cured productof the thermoplastic resin or may contains two or more cured products ofthe thermoplastic resin.

Examples of the curing agent for providing cured products of thethermoplastic resin described above can include isocyanate-type curingagents.

The cured products of the active ray-curable resin will be described inthe transfer layer of the second aspect.

(Transfer Layer of Second Aspect)

The transfer layer 10 of the second aspect has a single-layer structureconsisting of the protective layer 3 (see FIG. 1B) or a layeredstructure including the protective layer 3 (see FIG. 3A and FIG. 3B).The transfer layer 10 of the second aspect is not limited to the aspectshown and may have a configuration in which a release layer is providedbetween the substrate 1 and the transfer layer 10.

The protective layer 3 constituting the transfer layer 10 of the secondaspect contains a cured product of an active ray-curable resin. In otherwords, the protective layer 3 contains a resin obtained by irradiatingan active ray-curable resin with an active ray. According to thetransfer layer 10 of the second aspect containing a cured product of anactive ray-curable resin, it is possible to impart durability to a printobtained by transferring the transfer layer 10.

The transfer layer 10 of the second aspect further may satisfy the abovecondition 4. That is, the transfer layer 10 of the second aspect mayhave a configuration appropriately combined with the transfer layer 10of the first aspect.

The active ray-curable resin can be appropriately selected from thosedescribed in the thermal transfer sheet of the first embodiment of thepresent disclosure, and thus, a detailed description is omitted here.

There is not particular limitation with respect to the content of thecured product of an active ray-curable resin based on the total mass ofthe protective layer 3 constituting the transfer layer 10 of the secondaspect, but the content is preferably 30% by mass or more, morepreferably 50% by mass or more. The protective layer 3 also preferablycontains a cured product of a urethane (meth)acrylate, particularly, acured product of a polyfunctional urethane (meth)acrylate in the abovecontent, as the cured product of the active ray-curable resin. There isno particular limitation with respect to the upper limit value, but thevalue can be appropriately set depending on components to be optionallyadded and the like. One example thereof is 100% by mass.

The protective layer 3 constituting the transfer layer 10 of the secondaspect may contain other components in addition to the cured product ofan active ray-curable resin. Examples of the other components caninclude a filler. It is possible to improve the foil cutting property ofthe transfer layer 10 by causing the protective layer 3 to contain afiller.

There is no limitation with respect to the filler, and the filler isonly required to be appropriately selected for use from the first fillerand the second filler described in the thermal transfer sheet of thefirst embodiment of the present disclosure.

The protective layer 3 constituting the transfer layer 10 of the secondaspect preferably contains a filler having a volume average particlesize of 1 nm or more and 1 μm or less, more preferably contains a fillerhaving a volume average particle size of 1 nm or more and 50 nm or less,even more preferably contains a filler having a volume average particlesize of 7 nm or more and 25 nm or less. It is possible to furtherimprove the transferability by causing the protective layer 3constituting the transfer layer 10 of the second aspect to contain afiller having a volume average particle size within the range describedabove.

The content of the above filler based on the total mass of theprotective layer 3 constituting the transfer layer 10 of the secondaspect is preferably 10% by mass or more and 60% by mass or less, morepreferably 10% by mass or more and 50% by mass or less, even morepreferably 20% by mass or more and 40% by mass or less.

There is not particular limitation with respect to the thickness of theprotective layer 3 constituting the transfer layer 10 of the secondaspect, and the thickness is preferably 1 μm or more and 15 μm or less,preferably 2 μm or more and 6 μm or less. It is possible to furtherimprove the foil cutting property by setting the thickness of theprotective layer 3 constituting the transfer layer 10 of the secondaspect within this range. It is also possible to inhibit occurrence ofdefective transfer such as picking and chipping during transfer of thetransfer layer 10.

There is no limitation with respect to the method for forming theprotective layer 3 constituting the transfer layer 10 of the secondaspect, and the protective layer 3 can be formed using the method forforming the protective layer described in the thermal transfer sheet ofthe first embodiment of the present disclosure or the like.

(Adhesive Layer)

In the layered structure, the adhesive layer 5 also may be provided onthe protective layer 3 (see FIG. 3A and FIG. 3B). According to thethermal transfer sheet 100 of this aspect, it is possible to makeadhesion between the transfer layer 10 and the transfer receivingarticle 50 of the second aspect satisfactory when the transfer layer 10is transferred onto the transfer receiving article 50, due to thepresence of the adhesive layer 5.

The adhesive layer can be appropriately selected for use from theadhesive layer described in the thermal transfer sheet of the firstembodiment of the present disclosure.

(Initial Breakage Peeling-Off Force of Transfer Layer)

The thermal transfer sheet 100 of the second embodiment of the presentdisclosure has an initial breakage peeling-off force of 5 mN/m or lesswhen the transfer layer 10 is peeled from the side of the substrate 1under conditions of a peeling-off temperature of 20° C. or more and 40°C. or less and a peeling-off angle of 90°. That is, the thermal transfersheet 100 satisfies the above condition 3. According to the thermaltransfer sheet of the second embodiment of the present disclosure, it ispossible to transfer the transfer layer 10 of the first aspect and thesecond aspect onto the transfer receiving article 50 without causinghead untransfer to occur or with head untransfer inhibited.

(Method for Calculating Initial Breakage Peeling-Off Force 2)

The initial breakage peeling-off force in the thermal transfer sheet ofthe second embodiment of the present disclosure means a peeling-offforce to be calculated by the following method.

The thermal transfer sheet 100 including the substrate 1 and thetransfer layer 10 provided on the substrate 1 is cut into apredetermined width (hereinafter referred to as the width A). Note thatthe width of the transfer layer 10 at this time is also the width A.Then, as shown in FIG. 7, the cut thermal transfer sheet 100 is bondedonto a hot stage 200 of which temperature is adjusted to 20° C. usingtransparent double-sided tape (NICETACK® NW-15, Nichiban Co., Ltd.) suchthat the surface of the hot stage 200 is opposed to the surface of thetransfer layer 10. Then, the transfer layer 10 of the thermal transfersheet bonded is peeled from the side of the substrate 1 of the thermaltransfer sheet 100 under conditions of a peeling-off angle of 90° and apeel rate of 5 mm/sec., and the peeling-off force in the range from theinitial peeling-off portion (see FIG. 5 and FIG. 7) to a point 5 mm (5mm exclusive) distant in the peel-off direction is measured with apeeling-off force measurement device (Digital Force Gauge DPX-5, IMADACO., LTD.). Then, the initial breakage peeling-off force at apeeling-off temperature of 20° C. can be calculated by dividing thepeeling-off force having the maximum value among the peeling-off forcesmeasured (maximum peeling-off force in the measurement range) by thelength of the thermal transfer sheet in the width direction (width A).The initial breakage peeling-off force is calculated at peeling-offtemperatures other than this in the same manner. The peeling-off forcehaving the maximum value within the range of the peeling-offtemperatures is taken as the initial breakage peeling-off force of thetransfer layer 10 in the range of the peeling-off temperature of 20° C.or more and 40° C. or less. Note that the numerical value of the initialbreakage peeling-off force measured as described above, which iscalculated in the unit of g/cm, the unit of the numerical value to becalculated is converted to mN/m.

There is no particular limitation with respect to a device bringing theinitial breakage peeling-off force of the transfer layer 10 within therange described above, and for example, a release layer may be providedbetween the substrate 1 and the transfer layer 10 so as to satisfy theabove condition 3. Note that, in the case where the above condition 3 issatisfied without providing the release layer 2, providing a releaselayer is not required. Alternatively, as shown in FIG. 3B, the peellayer may be provided nearest from the substrate 1 among the layersconstituting the transfer layer 10 so as to satisfy the above condition3.

(Release Layer)

In the thermal transfer sheet 100 of the second embodiment of thepresent disclosure as one example for satisfying the above condition 3,the release layer 2, which directly contacts the transfer layer 10, isprovided between the substrate 1 and the transfer layer 10, as shown inFIG. 2, and this release layer contains a silicone resin. According tothe release layer 2 containing a silicone resin, it is possible to makeadjustments satisfying the above condition 3 by appropriately settingthe type, content, and the like of the silicone resin.

The silicone resin referred to herein means a compound having a siloxanebond in the molecular structure, and the concept thereof includes any ofunmodified silicone resins, modified silicone resins, andsilicone-modified resins. A silicone-modified resin can be prepared bycopolymerization of a polysiloxane group-containing vinyl monomer with avinyl monomer of another type, reaction of a thermoplastic resin with areactive silicone resin, or the like.

Examples of the silicone-modified resin can include silicone-modifiedresins prepared by a method of block copolymerizing a thermoplasticresin with a polysiloxane group-containing vinyl monomer, by a method ofgraft copolymerizing a thermoplastic resin with a polysiloxanegroup-containing vinyl monomer, or by a method of reacting athermoplastic resin with a reactive silicone resin. Examples ofthermoplastic resin constituting the silicone-modified resin can includeacryl resins, polyurethane, polyesters, epoxy resins, polyvinyl acetals,polycarbonate, and polyimides. Among these, a silicone-modified acrylresin can be suitably used.

The reactive silicone resin is a compound that has a polysiloxanestructure as the main chain and also has a reactive functional group(s)that react(s) with a functional group of the thermoplastic resin at oneend or both ends. Examples of the above reactive functional group caninclude an amino group, a hydroxyl group, an epoxy group, a vinyl group,and a carboxyl group.

As the silicone resin, a silsesquioxane can be suitably used. Therelease layer 2 of a preferable aspect contains a reaction product of aresin having a carboxyl group and a silsesquioxane having a functionalgroup that can react with the carboxyl group. According to the releaselayer 2 of the preferable aspect, it is possible to impart solventresistance to the release layer 2. The release layer 2 containing asilsesquioxane will be mentioned below.

Alternatively, the release layer 2 may contain a reaction product of asilsesquioxane having one functional group as the silsesquioxane and aresin having one different functional group that can react with the onefunctional group.

In addition to or instead of the above silicone resin, a peeling-offforce adjusting agent may be used to adjust the initial breakagepeeling-off force of the transfer layer to 5 mN/m or less.

Examples of the peeling-off force adjusting agent can include hydroxylgroup-containing resins having a hydroxyl value of 3 mgKOH/g or more and100 mgKOH/g or less, thermoplastic acryl resins, thermoplasticelastomers, rosin ester resins, polyesters, and thermoplastic resinshaving a glass transition temperature (Tg) of 30° C. or more and 130° C.or less.

Examples of the hydroxyl group-containing resin can include acryl resinscontaining a hydroxyl group, rosin resins containing a hydroxyl group,polyesters containing a hydroxyl group, polyvinyl acetals, polyvinylalcohol, polyester polyols, polyether polyols, and urethane polyols.

As the hydroxyl group-containing resin described above, hydroxylgroup-containing resins having a hydroxyl value of 3 mgKOH/g or more and100 mgKOH/g or less are preferable. Hydroxyl group-containing resinshaving a glass transition temperature (Tg) of 30° C. or more and 130° C.or less are also preferable.

The hydroxyl value referred to herein means a value measured by ahydroxyl value method in compliance with JIS-K-0070 (1992). The glasstransition temperature (Tg) referred to herein means a temperaturedetermined in compliance with JIS-K-7121 (2012) and based on measurementof the change in the heat quantity by DSC (differential scanningcalorimetry) (DSC method).

The release layer 2, as an example, contains 3% by mass or more and 45%by mass or less of the peeling-off force adjusting agent based on thetotal mass of the release layer 2.

The release layer 2 as an example to satisfy the above condition 3contains a filler. According to the release layer 2 containing a filler,it is possible to adjust the initial breakage peeling-off force when thetransfer layer 10 is transferred by appropriately setting the content ofthe filler.

More specifically, the higher the content of the filler contained in therelease layer 2, the smaller tends to be the value of the initialbreakage peeling-off force. Accordingly, it is possible to adjust theinitial breakage peeling-off force when the transfer layer 10 istransferred so as to satisfy the above condition 3 by appropriatelysetting the content of the filler based on the total mass of the releaselayer 2. With attention focused on the volume average particle size ofthe filler, in the case where the content of the filler is supposed tobe constant, the smaller the volume average particle size of the fillercontained in the release layer 2, the larger the number of fillerparticles per unit area of the release layer 2. Then, as the number offiller particles per unit area of the release layer 2 increases, thegloss feel of a print obtained by transferring the transfer layer 10 ina direct contact with the release layer 2 onto a transfer receivingarticle tends to decrease. Accordingly, in order to improve the glossfeel to be imparted to the print, it is only required to provide therelease layer 2 of which the volume average particle size of the filleris taken into consideration in addition to the content of the filler.

The release layer 2, as an example, contains 0.5% by mass or more and1.5% by mass or less of a filler having a volume average particle sizeof 2 μm or more and 5 μm or less based on the total mass of the releaselayer 2. According to the release layer 2 of this aspect, it is possibleto adjust the initial breakage peeling-off force when the transfer layeris transferred so as to satisfy the above condition 3, while inhibitingdecrease in the gloss feel to be imparted to a print to be obtained bytransferring the transfer layer onto a transfer receiving article. It isalso possible to set the stable-state peeling-off force mentioned belowwithin a preferable range. The filler can be appropriately selected foruse from the fillers described in the protective layer 3 mentionedabove.

Additionally, it is possible to adjust the initial breakage peeling-offforce so as to satisfy the above condition 3 while inhibiting decreasein the gloss feel of a print to be obtained by transferring the transferlayer 10 onto the transfer receiving article 50, by setting the surfaceroughness (SRa) of the face located on the side of the transfer layer 10of the release layer 2 to 0.05 μm or more and 0.08 μm or less, insteadof or in addition to allowing the release layer 2 to contain the fillerdescribed above. It is also possible to set the stable-state peeling-offforce mentioned below within a preferable range. As the measurementapparatus for the surface roughness (SRa), a three-dimensional surfaceroughness shape measuring apparatus (SURFCOM® 1400, TOKYO SEIMITSU CO.,LTD.) was used.

There is not particular limitation with respect to the thickness of therelease layer 2, and the thickness is preferably 0.3 μm or more and 2 μmor less, more preferably 0.5 μm or more and 1 μm or less.

Additionally, the glossiness (measurement angle: 20°) when the surfaceof the transfer layer 10 after transferred onto the transfer receivingarticle 50 is measured by a method in compliance with JIS-Z-8741 ispreferably 55% or more. As the measurement apparatus for glossiness, aglossiness meter (VG2000, Nippon Denshoku Industries Co. Ltd.) was used.

The thermal transfer sheet 100 of the second embodiment of the presentdisclosure satisfies the above condition 4, and the stable-statepeeling-off force when the transfer layer is peeled under conditions ofa peeling-off temperature of 20° C. or more and 40° C. or less and apeeling-off angle of 90° is preferably 0.19 mN/m or more and 4 mN/m orless, more preferably 0.19 mN/m or more and 1 mN/m or less. According tothe thermal transfer sheet 100 of this aspect, it is possible totransfer the transfer layer 10 onto a transfer receiving article with afurther satisfactory foil cutting property while inhibiting headuntransfer.

The stable-state peeling-off force referred to in the thermal transfersheet of the second embodiment of the present disclosure is apeeling-off force measured in a measurement range from a point 5 mmdistant from the initial peeling-off portion in the peel-off direction(see FIGS. 5 and 7) to a point 15 mm distant from the initialpeeling-off portion in the peel-off direction, that is, a measurementrange from a point 5 mm distant from the initial peeling-off portion inthe peel-off direction as the start point to a point 10 mm distant fromthis start point in the peel-off direction (peeling-off length: 10 mm)in the above Method for calculating an initial breakage peeling-offforce 2, and means a value obtained by dividing the peeling-off forcehaving the maximum value among the peeling-off forces measured (maximumpeeling-off force in the measurement range) by the length of the thermaltransfer sheet in the width direction (width A). In other words, in theabove method for calculating an initial breakage peeling-off force 2,the phrase “the peeling-off force in the range from the initialpeeling-off portion to a point 5 mm (5 mm exclusive) distant from theinitial peeling-off portion in the peel-off direction” may be replacedby “the peeling-off force in a range from a point 5 mm distant from theinitial peeling-off portion in the peel-off direction to a point 15 mmdistant from the initial peeling-off portion in the peel-off direction”.

There is not particular limitation with respect to a device for bringingthe stable-state peeling-off force into the above preferable range. Itis possible to adjust the stable-state peeling-off force within theabove preferable range by using the release layer 2 of the preferableaspect explained above.

<<Coating Liquid for Release Layer>>

Subsequently, a coating liquid for release layer according to theembodiment of the present disclosure (hereinafter also referred to asthe coating liquid for release layer of the present disclosure in somecases) will be described. Note that the coating liquid for release layerof the present disclosure is a coating liquid for forming the releaselayer of the thermal transfer sheet. A thermal transfer sheet 100including a release layer to be formed using the coating liquid forrelease layer of the present disclosure has a substrate 1, a releaselayer 2 provided on the substrate 1 (the upper surface of the substrate1 in the aspect shown), and a transfer layer 10 provided on the releaselayer 2, as shown in FIG. 8 and FIG. 9. The transfer layer 10 of theaspect shown in FIG. 8 and FIG. 9 has a layered structure in which aprotective layer 3 and an adhesive layer 5 are layered in this orderfrom the side of the substrate 1 (on the side of the release layer 2),but the transfer layer 10 may has a single-layer structure as shown inFIGS. 2A and 2B.

The thermal transfer sheet 100 including the release layer to be formedusing the coating liquid for release layer of the present disclosure isa thermal transfer sheet to be used for transferring the transfer layer10 onto an optional object (hereinafter referred to as a transferreceiving article).

The coating liquid for release layer of the present disclosure forforming the release layer of the thermal transfer sheet contains asilsesquioxane. According to the coating liquid for release layer of thepresent disclosure containing a silsesquioxane, it is possible to stablyform the release layer 2 having a small variation in the performancedifference using the coating liquid. In other words, it is possible toinhibit occurrence of a variation in the releasability of the releaselayer to be formed. Specifically, it is possible to stably form therelease layer 2 having a small variation in the performance differencewithout depending on the external environment when the release layer 2is formed by applying the coating liquid for release layer onto thesubstrate. More specifically, when the release layer 2 is formed byapplying the coating liquid for release layer onto the substrate 1followed by drying, it is possible to inhibit occurrence of a variationin the releasability to be imparted to the release layer to be formeddue to the influence of the moisture contained in the atmosphere.Thereby, it is possible to stably form the release layer 2 having asmall variation in the performance difference. This acting effect ispresumed to be caused by the skeletal structure of the silsesquioxane.Note that, in the case where a coating liquid that does not satisfy therequirement for the coating liquid for release layer of the presentdisclosure is used as the coating liquid for release layer, a variationtends to occur in the releasability of the release layer to be formeddue to the influence of the moisture in the atmosphere, in comparisonwith the case where the release layer is formed using the coating liquidfor release layer of the present disclosure. It is also possible to forma release layer having satisfactory solvent resistance using the coatingliquid for release layer of the present disclosure (except for the casewhere the coating liquid for release layer is caused to contain asilsesquioxane and a resin having a carboxyl group having an acid valueof 10 mgKOH/g or more mentioned below).

The silsesquioxane referred to herein means a siloxane compound of whichmain chain skeleton is a siloxane-type compound composed of a Si—O bond(the following formula 1) and which has 1.5 oxygen atoms in the unitcomposition. Note that the silsesquioxane also includes ones in which adifferent functional group is introduced to the organic group R in thefollowing formula 1:

(RSiO_(1.5))_(n)  (Formula 1)

wherein R is an organic group.

Examples of the skeletal structure of the silsesquioxane can includevarious skeletal structure such as a random-type structure, a cage-typestructure, and a ladder-type structure, and any of the skeletalstructures can be used. Among these, silsesquioxanes of the random-typeor cage-type skeletal structure are preferable, and silsesquioxanes ofthe random-type are particularly preferable.

There is not particular limitation with respect to the mass of thesilsesquioxane, and the content of the silsesquioxane is preferably 80%by mass or more and 100% by mass or less, more preferably 85% by mass ormore and 95% by mass or less, based on the total mass of the coatingliquid for release layer of the present disclosure (with the provisothat the mass of the solvent is excluded). Note that the content of thesilsesquioxane is not limited thereto, in the case where the coatingliquid for release layer of the present disclosure contains asilsesquioxane and additionally another resin that can react with thesilsesquioxane.

The coating liquid for release layer of the present disclosure maycontain a silsesquioxane singly or may contain two or moresilsesquioxanes.

The coating liquid for release layer of the present disclosure maycontain a silsesquioxane having one functional group and a resin havingone different functional group that can react with the one functionalgroup. According to the coating liquid of this aspect, it is possible toform the release layer 2 containing a reaction product of asilsesquioxane having one functional group and a resin having onedifferent functional group that can react with the one functional group.Thus, according to the coating liquid of this aspect, it is possible toform the release layer 2 having releasability as well as an additionalfunction due to the acting effect of the resin having one differentfunctional group by using the coating liquid.

A preferable coating liquid for release layer of the present disclosurecontains a resin having a carboxyl group, as the resin having onedifferent functional group. In this case, it is only required to use asilsesquioxane having a functional group that can react with the resinhaving a carboxyl group, as the silsesquioxane. Accordingly, the releaselayer 2 of a preferable aspect contains a reaction product of a resinhaving a carboxyl group and a silsesquioxane.

According to the coating liquid for release layer of the presentdisclosure containing a resin having a carboxyl group and asilsesquioxane having a functional group that can react with thecarboxyl group, it is possible to impart higher releasability to arelease layer to be formed using the coating liquid.

Examples of the silsesquioxane having a functional group that can reactwith a resin having a carboxyl group can include silsesquioxanes havingan epoxy group. Besides these, silsesquioxanes having a hydroxyl group,an amino group, or a mercapto group, for example, can be used.

Examples of the resin having a carboxyl group can include acrylicpolymers. Examples of the acrylic polymer can include polymers of(meth)acrylic acid or derivatives thereof, polymers of (meth)acrylicacid ester or derivatives thereof, copolymers of (meth)acrylic acid andanother monomer or derivatives thereof, and copolymers of (meth)acrylicacid ester and another monomer or derivatives thereof. Besides these,examples of the resin having a carboxyl group can include polyesters,polyurethanes, silicone resins, and rosin resin having a carboxyl group.

A coating liquid of a more preferable aspect contains a resin having anacid value of 10 mgKOH/g or more as the above resin having a carboxylgroup. According to the coating liquid of this aspect, it is possible toimpart higher releasability and additionally high solvent resistance toa release layer to be formed using the coating liquid. Accordingly, itis possible to inhibit the release layer to be formed using the coatingliquid from being damaged by an organic solvent. Specifically, even inthe case where a coating liquid for transfer layer containing an organicsolvent is applied onto a release layer to be formed using a coatingliquid for release layer of the present disclosure in order to form athermal transfer sheet, it is possible to inhibit the release layer tobe formed using a coating liquid for release layer of the presentdisclosure from being damaged by an organic solvent by imparting solventresistance to the release layer. Accordingly, the release layer 2 of thepreferable aspect contains a reaction product of a resin having acarboxyl group having an acid value of 10 mgKOH/g and a silsesquioxane.Note that the acid value referred to herein means the number ofmilligrams of potassium hydroxide necessary for neutralizing the acidcomponent (e.g., carboxyl group) contained in 1 g of a polymer and canbe measured by a method in compliance with JIS-K-2501 (2003). There isnot particular limitation with respect to the upper limit of apreferable acid value, and one example thereof is 200 mgKOH/g.

In the case where the coating liquid for release layer of the presentdisclosure is a coating liquid containing a silsesquioxane having anepoxy group and a resin having a carboxyl group, the mass of thesilsesquioxane having an epoxy group as an example is 10% by mass ormore and 95% by mass or less, and the mass of the resin having acarboxyl group is 5% by mass or more and 90% by mass or less based onthe total mass of the coating liquid (with the proviso that the mass ofthe solvent is excluded). In this case, based on the total mass of thereaction product of a resin having a carboxyl group and asilsesquioxane, the mass of the component derived from thesilsesquioxane is 10% by mass or more and 95% by mass or less, and themass of the component derived from the resin having a carboxyl group is5% by mass or more and 90% by mass or less. As another example, the massof the silsesquioxane having an epoxy group is 10% by mass or more and40% by mass or less, and the mass of the resin having a carboxyl groupis 60% by mass or more and 90% by mass or less. In the case where thecoating liquid for release layer of the present disclosure contains areaction catalyst to be mentioned below, the total mass of thesilsesquioxane having an epoxy group and the resin having a carboxylgroup is 80% by mass or more and 96% by mass or less, preferably 85% bymass or more and 91% by mass or less, based on the total mass of thecoating liquid as an example (with the proviso that the mass of thesolvent is excluded).

The coating liquid for release layer of the present disclosurepreferably contains a reaction catalyst. There is no particularlimitation with respect to the reaction catalyst, and the reactioncatalyst is only required to be determined in accordance with thefunctional group possessed by the silsesquioxane contained in thecoating liquid for release layer of the present disclosure or thefunctional group of the resin that reacts with the silsesquioxane,contained as required. For example, in the case where the coating liquidfor release layer of the present disclosure is a coating liquidcontaining a silsesquioxane having an epoxy group and a resin having acarboxyl group, the coating liquid for release layer of the presentdisclosure contains, as the reaction catalyst, more preferably anorganic metal compound (including a chelate (complex) of the organicmetal compound), contains more preferably an organic zirconium chelator.

There is not particular limitation with respect to the content of thereaction catalyst, and the content is preferably 4% by mass or more and20% by mass or less, more preferably 9% by mass or more and 15% by massor less, based on the total mass of the coating liquid for release layerof the present disclosure (with the proviso that the mass of the solventis excluded).

The coating liquid for release layer of the present disclosure alsocontains a solvent for dissolving or dispersing the silsesquioxane.There is not particular limitation with respect to the solvent, and theexample thereof can include organic solvents such as methyl ethylketone, toluene, xylene, methyl isobutyl ketone, ethyl acetate,isopropyl alcohol, and ethanol, and water.

The coating liquid for release layer of the present disclosure may alsocontain optional components, in addition to a silsesquioxane, a resinthat can react with the silsesquioxane, and a reaction catalyst.Examples of the optional components can include waxes, silicone wax,silicone resins, silicone-modified resins, fluorine resins,fluorine-modified resins, polyvinyl alcohol, acryl resins, rosin resins,polyesters, polyvinyl acetals such as polyvinyl butyral and polyvinylacetoacetal, polyester polyol, polyether polyol, and urethane polyol(with the proviso that, among these resins, a silsesquioxane and a resinthat can react with the silsesquioxane are excluded). The content ofthese optional components is preferably 10% by mass or less based on thetotal mass of the coating liquid for release layer of the presentdisclosure (with the proviso that the mass of the solvent is excluded).

The coating liquid for release layer of the present disclosure can beobtained by dispersing or dissolving a silsesquioxane, and a resin thatcan react with the silsesquioxane, and a reaction catalyst, which areadded as required, and further, optional components into a suitablesolvent.

<<Thermal Transfer Sheet of Third Embodiment>>

As shown in FIGS. 2A and 2B, FIG. 8, and FIG. 9, a thermal transfersheet according to a third embodiment of the present disclosure(hereinafter referred to as the thermal transfer sheet of the thirdembodiment of the present disclosure) has a substrate 1, a release layer2 provided on the substrate, and a transfer layer 10 provided on therelease layer 2. The transfer layer 10 is provided peelably from therelease layer 2.

(Release Layer)

In the thermal transfer sheet 100 of the third embodiment of the presentdisclosure, the release layer 2 contains a silsesquioxane. According tothe thermal transfer sheet 100 of the third embodiment of the presentdisclosure containing this release layer 2, it is possible to impartstable releasability to the release layer 2.

Note that the silsesquioxane contained in the release layer 2 alsoincludes ones in which a different functional group is introduced to theorganic group R of the silsesquioxane of the above formula 1.

Whether the release layer contains a silsesquioxane or not can beidentified by the following method.

Measuring Method:

²⁹Si cross polarization (CP)/magic-angle spinning (MAS) NMR Measurementconditions:

Apparatus name: BRUKER nuclear magnetic resonance apparatus (NMR) AVANCEIII HD

Resonance frequency: 79.51 MHz

Repetition time: 4 sec.

Contact time: 3 msec.

Sample rotation number: 5 kHz

Specifically, a sample is prepared by scraping off the release layer ofa target thermal transfer sheet. When this sample is measured by theabove measuring method under the above measuring conditions, whether therelease layer contains a silsesquioxane or not can be identified bywhether the peaks of the following T components derived from thesilsesquioxane that appear in the chemical shift range of −45 ppm to −70ppm can be confirmed or not. Peaks derived from silica (SiO₂) appear inthe chemical shift range of −80 to −110 ppm. In this respect, it ispossible to clearly distinguish whether the component contained in therelease layer is silica or the silsesquioxane. Note that FIGS. 12A and12B are one example of measurement results of a release layer containinga silsesquioxane measured by the above measurement method.

The release layer 2 as an example contains a reaction product of asilsesquioxane having an epoxy group and a resin having a carboxylgroup. According to the thermal transfer sheet 100 of this aspect, it ispossible to further impart solvent resistance to the release layer 2.The release layer 2 containing such a reaction product can be obtainedby applying a coating liquid containing a silsesquioxane having an epoxygroup and a resin having a carboxyl group onto the substrate 1, followedby drying. In order to facilitate the reaction, the reaction catalystdescribed for the coating liquid for release layer of the presentdisclosure may be used.

Alternatively, the release layer 2 can be also obtained by preparing areaction product obtained by allowing a silsesquioxane having an epoxygroup to react with a resin having a carboxyl group in advance, applyinga coating liquid containing this reaction product onto the substrate 1,followed by drying.

In a more preferable thermal transfer sheet 100 of the third embodimentof the present disclosure, the release layer 2 contains a reactionproduct of a silsesquioxane having an epoxy group and a resin containinga carboxyl group and having an acid value of 10 mgKOH/g or more.According to the thermal transfer sheet 100 comprising the release layercontaining this reaction product, it is possible to further improve thesolvent resistance to be imparted to the release layer 2.

In the above release layer 2, the content of the reaction product of thesilsesquioxane having an epoxy group and the resin having a carboxylgroup is preferably 75% by mass or more and 95% by mass or less, morepreferably 80% by mass or more and 90% by mass or less, based on thetotal mass of the release layer 2.

The release layer 2 of the thermal transfer sheet of the thirdembodiment of the present disclosure can be formed with appropriateselection of the coating liquid for release layer described in thecoating liquid for release layer of the present disclosure, and adetailed description is omitted here.

There is not particular limitation with respect to the thickness of therelease layer 2, and the thickness is preferably 0.3 μm or more and 2 μmor less, more preferably 0.5 m or more and 1 μm or less.

The release layer 2 can be obtained by applying the coating liquid forrelease layer of the present disclosure described above onto thesubstrate 1, followed by drying.

(Substrate)

The substrate 1 has the release layer 2 and the transfer layer 10constituting the thermal transfer sheet 100 of the third embodiment ofthe present disclosure. There is no limitation with respect to thesubstrate, and the substrate described in the thermal transfer sheet 100of the first embodiment described above can be appropriately selectedand used.

(Transfer Layer)

As shown in FIG. 8 and FIG. 9, the transfer layer 10 is provided on therelease layer 2. The transfer layer 10 is a layer to be peeled at theface on the side opposed to the substrate 1 of the transfer layer 10 asa peel interface, which layer moves onto a transfer receiving articleduring thermal transfer. Specifically, in the thermal transfer sheet 100of the third embodiment of the present disclosure, the transfer layer 10is provided on the release layer 2. The transfer layer 10 is peeled fromthe release layer 2 and moves onto a transfer receiving article duringthermal transfer. The transfer layer 10 as one example has a layeredstructure in which the protective layer 3 and the adhesive layer 5 arelayered in this order from the side of the substrate 1. Note that thetransfer layer 10 may have a single-layer structure composed of onelayer or may have a layered structure in which two or more layers arelayered. The transfer layers 10 of the first embodiment and the secondembodiment of the present disclosure also may be appropriately selectedand used. Hereinbelow, a case in which the transfer layer 10 is atransfer layer in which the protective layer 3 and the adhesive layer 5are layered in this order from the side of the substrate 1 will bemainly described.

(Protective Layer)

The protective layer 3 included in the transfer layer 10 as an exampleis a layer to impart durability to a print obtained by transferring thetransfer layer 10 onto a transfer receiving article. Note that theprotective layer 3 is located nearest from the substrate 1 among thelayers constituting the transfer layer 10 and is located on theoutermost surface in a print obtained by transferring the transfer layer10 onto a transfer receiving article. That is, the thermal transfersheet of this aspect has a structure in which the transfer layer 10 ispeeled at the interface between the release layer 2 and the protectivelayer 3.

There is no particular limitation with respect to the protective layer3, and protective layers conventionally known in the field of thermaltransfer sheets and protective layer transfer sheets can beappropriately selected and used. Examples of the components constitutingthe protective layer 3 can include polyesters, polystyrene, acrylresins, polyurethane, acryl urethane, resins obtained bysilicone-modifying each of these resins, and mixtures of each of theseresins.

The protective layer 3 of a preferable aspect to impart durability to aprint contains a cured product of an active ray-curable resin. In thethermal transfer sheet 100 of the third embodiment of the presentdisclosure, as the protective layer, the protective layers 3 of thefirst embodiment and the second embodiment of the present disclosure canbe suitably used.

(Adhesive Layer)

As shown in FIG. 8 and FIG. 9, the adhesive layer 5 described in thethermal transfer sheet of the first embodiment of the present disclosuremay be provided on the protective layer 3.

There can also be used a structure in which a receiving layer, insteadof the adhesive layer 5, is provided on the protective layer 3 (notshown). The same applies to the thermal transfer sheets of the firstembodiment and the second embodiment of the present disclosure. Examplesof the materials for the receiving layer can include polyolefins such aspolypropylene, halogenated resins such as polyvinyl chloride orpolyvinylidene chloride, vinyl resins such as polyvinyl acetate, vinylchloride—vinyl acetate copolymers, ethylene—vinyl acetate copolymers, orpolyacrylic acid esters, polyesters such as polyethylene terephthalateor polybutylene terephthalate, copolymers of an olefin such aspolystyrene, polyamide, ethylene, or propylene and another vinylpolymer, ionomers, or cellulose resins such as cellulose diacetate,polycarbonate, and solvent-based resins such as acryl resins. Thethickness of the receiving layer is preferably 0.5 μm or more and 10 μmor less, more preferably 1 μm or more and 3 μm or less.

The transfer layer 10 can also have a single-layer structure composed ofone layer. For example, in the case where a measure to improve theadhesion with the transfer layer 10 is taken on the side of a transferreceiving article, the transfer layer 10 may have a single-layerstructure consisting of the protective layer 3. The transfer layer 10may also has a single-layer structure consisting of an adhesive layer.The transfer layer 10 may also have a layered structure composed of theprotective layer 3 and the receiving layer. The transfer layer 10 mayalso has a single-layer structure consisting of an adhesive layer. Thetransfer layer 10 may also has other structure than these. That is, inthe thermal transfer sheet 100 of the third embodiment of the presentdisclosure is not limited in any way with respect to the transfer layer10, and the transfer layer 10 is only required to be peeled at theinterface with the release layer 2 and transferred onto a transferreceiving article.

In the preferable thermal transfer sheet 100 of the third embodiment ofthe present disclosure, the transfer layer 10 has a layered structure inwhich the protective layer 3 and the adhesive layer 5 described aboveare layered in this order, in order to impart sufficient durability to aprint onto which the transfer layer 10 is transferred. The adhesivelayer can also have a dye-receiving ability. Alternatively, the thermaltransfer sheet 100 can also has a structure in which the transfer layer10 has the layered structure in which the protective layer 3 of thepreferable aspect and a receiving layer are layered in this order and anadhesive property is imparted to the receiving layer.

(Adhesion Layer)

In the case where the adhesion force between the substrate 1 and therelease layer 2 is lower than the adhesion force between the releaselayer 2 and the transfer layer 10, an adhesion layer 7 (also referred toas an anchor coat layer or the like in some cases) may be providedbetween the substrate 1 and the release layer 2, as shown in FIG. 9,such that the adhesion force between the substrate 1 and the releaselayer 2 becomes higher than the adhesion force between the release layer2 and the transfer layer 10. Note that the adhesion layer 7 is anoptional constituent in the thermal transfer sheet 100 of the secondembodiment. For example, in the case where the adhesion force betweenthe substrate 1 and the release layer 2 is higher than the adhesionforce between the release layer 2 and the transfer layer 10 byconducting an easily-adhesive treatment on the substrate 1, as describedabove, it is not particularly necessary to provide the adhesion layer 7.As components of the adhesion layer, it is only required that componentsthat can make the adhesion force between the substrate 1 and the releaselayer 2 higher than the adhesion force between the release layer 2 andthe transfer layer 10 are appropriately selected and used.

(Dye Layer)

In the thermal transfer sheet of the various embodiments describedabove, a dye layer (not shown) may be provided together with thetransfer layer 10 in a frame-sequential manner. The dye layer may be asingle dye layer or may be one in which a plurality of dye layers, forexample, two or all of a yellow dye layer, a magenta dye layer, and acyan dye layer, are provided in a frame-sequential manner. Additionally,the dye layer may be one in which a fusible layer and the like areprovided together with these dye layers in a frame-sequential manner.

(Back Face Layer)

In the thermal transfer sheet of the various embodiments, it is possibleto also provide a back face layer (not shown) aimed at improving theheat resistance, driving stability, and the like on the face on theopposite side of the face of the substrate 1 on which the transfer layer10 is provided.

The back face layer may be formed by appropriately selecting resin(s)from the conventionally known thermoplastic resins and the like.Examples of such a thermoplastic resin can include polyesters,polyacrylic acid esters, polyvinyl acetate, styrene acrylate,polyurethane, polyolefins such as polyethylene and polypropylene,polystyrene, polyvinyl chloride, polyethers, polyamides, polyimides,polyamideimides, polycarbonate, polyacrylamide, polyvinyl chloride,polyvinyl acetals such as polyvinyl butyral and polyvinyl acetoacetal,and silicone-modified forms of these.

Additionally, the back face layer preferably contains various additives,for example, a peel agent such as a wax, a higher fatty acid amide, aphosphoric acid ester compound, metal soap, silicone oil, or asurfactant, an organic powder such as a fluorine-containing resin, andinorganic particles such as silica, clay, talc, or calcium carbonate, inorder to improve the slipping property, particularly preferably containsat least one of a phosphoric acid ester or metal soap.

The back face layer can be formed by, for example, dispersing ordissolving the thermoplastic resin described above and various additivesto be added as required into a suitable solvent to prepare a coatingliquid for back face layer, applying this coating liquid onto thesubstrate 1, followed by drying. The thickness of the back face layer ispreferably 0.1 μm or more and 5 μm or less, more preferably 0.3 μm ormore and 2.0 μm or less, from the viewpoint of improvement in the heatresistance and the like.

Hereinabove, the thermal transfer sheet of the present disclosure hasbeen concretely described with reference to the thermal transfer sheetsof the first embodiment to the third embodiment, but the constituentsdescribed in the thermal transfer sheet of the various embodiments maybe appropriately combined to form a thermal transfer sheet. The thermaltransfer sheet of a preferable aspect fulfills the configuration of thethermal transfer sheets of two or more of the embodiments among thethermal transfer sheets of the first embodiment to the third embodiment.The thermal transfer sheet of a more preferable aspect fulfills theconfigurations of the thermal transfer sheets of the first embodiment tothe third embodiment. Specifically, the thermal transfer sheet 100 ofthis configuration has a substrate 1, a release layer 2 provided on thesubstrate 1, and a transfer layer 10 provided on the release layer 2.The transfer layer 10 is provided peelably from the release layer 2, andthe release layer 2 contains a silsesquioxane. The initial breakagepeeling-off force when the transfer layer 10 is peeled under conditionsof a peeling-off temperature of 20° C. or more and 40° C. or less and apeeling-off angle of 90° is 5 mN/m or less. The initial breakagepeeling-off force when the transfer layer 10 is peeled under conditionsof a peeling-off temperature of 20° C. or more and 70° C. or less and apeeling-off angle of 60° or more is 1.97 mN/m or less. The scratchhardness (a sapphire needle having a tip radius of 0.1 mm is used) whenthe face located on the side of the substrate 1 of the transfer layer 10is measured by a method in compliance with JIS-K-5600-5-5 is 200 g ormore.

According to the thermal transfer sheet of this aspect, it is possibleto sufficiently inhibit occurrence of head untransfer when the transferlayer is transferred onto a transfer receiving article and impartsufficient durability to a print obtained by transferring the transferlayer onto the transfer receiving article. It is also possible to impartstable releasability to the release layer.

<Transfer of Transfer Layer>

Examples of the method for transferring the transfer layer 10 onto atransfer receiving article using the thermal transfer sheet 100 of eachembodiment of the present disclosure described as above can includeknown methods such as hot stamping (foil stamping) with a thermalstamper, entire surface or stripe transfer with a heat roll, and thermalprinters (also referred to as thermal transfer printers in some cases)with a thermal head (thermal printing head).

<Transfer Receiving Article>

Transfer receiving articles onto which the transfer layer 10 of thethermal transfer sheet is to be transferred are not limited in any way.Examples thereof can include plastic films such as IC cards and IDcards, conventionally known thermal transfer image-receiving sheets,plastic cards mainly composed of vinyl chloride, a vinyl chloride-vinylacetate copolymer, or polycarbonate, plain paper, wood-free paper,natural fiber paper, coated paper, tracing paper, glass, metals,ceramics, woods, and fabrics. As the transfer receiving article, onehaving a predetermined image also can be used. The transfer receivingarticle may be colored or may have transparency. The transfer receivingarticle may be one composed of a single layer or may be one composed ofa plurality of layers.

Examples of the plastic film include polyesters such as polyethyleneterephthalate (PET), polybutylene terephthalate (PBT), polyethylenenaphthalate (PEN), polyethylene terephthalate—isophthalate copolymers,terephthalic acid—cyclohexanedimethanol—ethylene glycol copolymers, andpolyethylene terephthalate/polyethylene naphthalate coextruded films,polyamides such as nylon 6 and nylon 6,6, polyolefins such aspolyethylene, polypropylene, and polymethylpentene, vinyl resin such aspolyvinyl chloride, acryl resins such as poly(meth)acrylate andpolymethyl (meth)acrylate, imide resins such as polyimide and polyetherimide, engineering resins such as polyarylate, polysulfone, polyethersulfone, polyphenylene ether, polyphenylene sulfide (PPS), polyaramid,polyether ketone, polyether nitrile, polyether ether ketone, andpolyether sulfite, styrene resins such as polystyrene, high impactpolystyrene, acrylonitrile—styrene copolymers (AS resins), andacrylonitrile—butadiene—styrene copolymers (ABS resins), cellulose-basedfilms such as cellophane, cellulose acetate, and nitrocellulose, andpolycarbonate. The plastic film may be a copolymer resin or mixedproduct (including an alloy) mainly based on the resins described above.

Usually in IC cards, ID cards, and the like, designability and securityare required. Thus, such cards in which a printed layer, a hologramlayer, or the like is provided on the surface thereof in advance alsocan be used as transfer receiving articles.

<<Method for Producing Thermal Transfer Sheet>>

Hereinbelow, a method for producing the thermal transfer sheet accordingto the embodiment of the present disclosure (hereinafter also referredto as the production method of the present disclosure in some cases)will be described. The production method of the present disclosurecomprises a step of forming a release layer on a substrate, and a stepof forming a transfer layer on the release layer. Then, in theproduction method of the present disclosure, the step of forming arelease layer is a step of applying the coating liquid for release layerof the present disclosure onto the substrate, followed by drying.

Note that the step of applying the coating liquid for release layer onthe substrate, followed by drying includes not only a step of applyingthe coating liquid for release layer directly onto the substrate,followed by drying but also a step of applying the coating liquid forrelease layer indirectly onto the substrate, followed by drying, inother words, a step of applying the coating liquid for release layeronto a layer optionally provided on the substrate, followed by drying.

According to the production method of the present disclosure, it ispossible to stably impart releasability to the release layer of thethermal transfer sheet to be produced by the production method.Additionally, it is possible to impart releasability and solventresistance to the release layer by use of the coating liquid of thepreferable aspect described above as the coating liquid for releaselayer of the present disclosure.

Particularly, even in the case where, after the step of forming arelease layer, a coating liquid containing an organic solvent as thecoating liquid for forming the transfer layer is used in the step offorming a transfer layer on the release layer, it is possible to inhibitthe release layer from being damaged by the organic solvent contained inthe coating liquid by imparting solvent resistance together withreleasability to the release layer.

As the coating liquid for release layer to be used in the step offorming a release layer, the coating liquids described in the coatingliquid for release layer of the present disclosure described above canbe appropriately selected and used, and a detailed description isomitted here.

In the step of forming a transfer layer, a transfer layer of asingle-layer structure may be formed by applying a first coating liquidfor transfer layer onto the release layer, followed by drying.Alternatively, after a first transfer layer is formed by coating a firstcoating liquid for transfer layer on the release layer, followed bydrying, a second transfer layer may be formed by applying a secondcoating liquid for transfer layer onto the first transfer layer,followed by drying. In other words, the step may be a step of forming atransfer layer of a single-layer structure or may be a step of forming atransfer layer of a layered structure.

In the case where a transfer layer of a layered structure is formed, astep of forming an optional layer, for example, a primer layer, betweenthe transfer layers also may be included. The production method of thepresent disclosure may also include a step of forming an optional layer,for example, an adhesion layer, between the substrate and the releaselayer. The production method may also include a step of forming a backface layer on the face on the opposite side of the face of the substrateon which the release layer is formed.

EXAMPLES

Next, the present invention will be described more concretely withreference to examples and comparative examples. Hereinbelow, unlessotherwise particularly specified, the expression of part(s) or % meansthat by mass, representing a mass (amount fed) not in terms of solidcontent.

Example 1-1

As a substrate, a PET (polyethylene terephthalate) film having athickness of 25 μm was used. A coating liquid for peel layer having thefollowing composition was applied onto one face of this substrate, andthen dried to form a peel layer having a thickness of 0.5 μm.Subsequently, onto the peel layer, a coating liquid for protective layer1 having the following composition was coated, and then dried. Then, aUV exposure machine (Fusion UV, F600V, LH10 lamp, H valve, cold-typereflector) was used to apply ultraviolet irradiation under conditionsshown in the following table 1 to form a protective layer having athickness of 4.5 μm. Then, a coating liquid for primer layer 1 havingthe following composition was applied onto the protective layer, andthen dried to form a primer layer having a thickness of 0.8 μm. Then, acoating liquid for adhesive layer having the following composition wasapplied onto the primer layer, and then dried to form an adhesive layerhaving a thickness of 0.6 μm. Thus, a thermal transfer sheet of Example1-1 was obtained, in which the transfer layer was provided on one faceof the substrate. Note that the transfer layer of the thermal transfersheet of Example 1-1 has a layered structure in which the peel layer,the protective layer, the primer layer, and the adhesive layer arelayered in this order from the side of the substrate.

<Coating liquid for peel layer> Acryl resin  95 parts (DIANAL(R) BR-87,Mitsubishi Chemical Corporation) Polyester  5 parts (Vylon(R) 200,TOYOBO CO., LTD.) Toluene 200 parts Methyl ethyl ketone 200 parts

<Coating liquid for protective layer 1> Polyfunctional acrylate  18parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) Urethaneacrylate  18 parts (NK oligomer EA1020, Shin Nakamura Chemical Co.,Ltd.) Urethane acrylate  10 parts (NK ester U-15HA, Shin NakamuraChemical Co., Ltd.) Reactive binder (containing an unsaturated group)  4parts (NK polymer C24T, Shin Nakamura Chemical Co., Ltd.) First filler(volume average particle size: 0.7 μm)  10 parts (XC99-A8808manufactured by Momentive Performance Materials Japan LLC) Second filler(volume average particle size: 12 nm)  34 parts (MEK-AC2140Z, NissanChemical Industries, Ltd.) Surfactant (acrylic surfactant)  1 part(LF-1984, Kusumoto Chemicals, Ltd.) Photo-polymerization initiator  5parts (Irgacure(R) 184, BASF Japan Ltd.) Toluene 100 parts Methyl ethylketone 100 parts

<Coating liquid for primer layer 1> Polyester 3.3 parts (Vylon(R) 200,TOYOBO CO., LTD.) Vinyl chloride-vinyl acetate copolymer 2.7 parts(SOLBIN(R) CNL, Nissin Chemical Co., Ltd.) Polyisocyanate curing agent1.5 parts (TAKENATE(R) D110N, Mitsui Chemicals, Inc.) Toluene 3.3 partsMethyl ethyl ketone 6.7 parts

<Coating liquid for adhesive layer> Modified polyolefin 31.5 parts(Arrowbase(R) SQ1221NQ, Unitika Ltd.) (Meth)acryl resin (Tg: 76° C.) 3.5 parts (JURYMER(R) AT-613, Toagosei Co., Ltd.) Water   36 partsIsopropyl alcohol   18 parts

Example 1-2

A thermal transfer sheet of Example 1-2 was obtained exactly in the samemanner as in Example 1-1 except that the formation conditions for theprotective layer were replaced by the conditions shown in the followingtable 1.

Example 1-3

A thermal transfer sheet of Example 1-3 was obtained exactly in the samemanner as in Example 1-1 except that the coating liquid for protectivelayer 1 was replaced by a coating liquid for protective layer 2 havingthe following composition and the formation conditions for theprotective layer were replaced by the conditions shown in the followingtable 1.

<Coating liquid for protective layer 2> Polyfunctional acrylate  19parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) Urethaneacrylate  19 parts (NK oligomer EA1020, Shin Nakamura Chemical Co.,Ltd.) Urethane acrylate  11 parts (NK ester U-15HA, Shin NakamuraChemical Co., Ltd.) Reactive binder (containing an unsaturated group)  5parts (NK polymer C24T, Shin Nakamura Chemical Co., Ltd.) First filler(volume average particle size: 0.7 μm)  5 parts (XC99-A8808 manufacturedby Momentive Performance Materials Japan LLC) Second filler (volumeaverage particle size: 12 nm)  34 parts (MEK-AC2140Z, Nissan ChemicalIndustries, Ltd.) Surfactant (acrylic surfactant)  1 part (LF-1984,Kusumoto Chemicals, Ltd.) Photo-polymerization initiator  5 parts(Irgacure(R) 184, BASF Japan Ltd.) Toluene 100 parts Methyl ethyl ketone100 parts

Example 1-4

A thermal transfer sheet of Example 1-4 was obtained exactly in the samemanner as in Example 1-1 except that the coating liquid for protectivelayer 1 was replaced by a coating liquid for protective layer 3 havingthe following composition and the formation conditions for theprotective layer were replaced by the conditions shown in the followingtable 1.

<Coating liquid for protective layer 3> Polyfunctional acrylate  16parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) Urethaneacrylate  16 parts (NK oligomer EA1020, Shin Nakamura Chemical Co.,Ltd.) Urethane acrylate  9 parts (NK ester U-15HA, Shin NakamuraChemical Co., Ltd.) Reactive binder (containing an unsaturated group)  4parts (NK polymer C241, Shin Nakamura Chemical Co., Ltd.) First filler(volume average particle size: 0.7 μm)  15 parts (XC99-A8808manufactured by Momentive Performance Materials Japan LLC) Second filler(volume average particle size: 12 nm)  34 parts (MEK-AC2140Z, NissanChemical Industries, Ltd.) Surfactant (acrylic surfactant)  1 part(LF-1984, Kusumoto Chemicals, Ltd.) Photo-polymerization initiator  5parts (Irgacure(R) 184, BASF Japan Ltd.) Toluene 100 parts Methyl ethylketone 100 parts

Example 1-5

A thermal transfer sheet of Example 1-5 was obtained exactly in the samemanner as in Example 1-1 except that the formation conditions for theprotective layer were replaced by the conditions shown in the followingtable 1.

Example 1-6

As a substrate, a PET (polyethylene terephthalate) film having athickness of 25 μm was used. A coating liquid for release layer 1 havingthe following composition was applied onto one face of this substrate,and then dried to form a release layer having a thickness of 0.6 μm.Subsequently, onto the release layer, the coating liquid for protectivelayer 1 having the above composition was applied and then dried. Then, aUV exposure machine (Fusion UV, F600V, LH10 lamp, H valve, cold-typereflector) was used to apply ultraviolet irradiation under conditionsshown in the following table 1 to form a protective layer having athickness of 4.5 μm. Then, the coating liquid for primer layer 1 havingthe above composition was applied onto the protective layer, and thendried to form a primer layer having a thickness of 0.8 μm. Then, thecoating liquid for adhesive layer having the above composition wasapplied onto the primer layer, and then dried to form an adhesive layerhaving a thickness of 0.6 μm. Thus, a thermal transfer sheet of Example1-6 was obtained, in which the transfer layer was provided on one faceof the substrate. Note that the transfer layer of the thermal transfersheet of Example 1-6 has a layered structure in which the protectivelayer, the primer layer, and the adhesive layer are layered in thisorder from the side of the substrate.

<Coating liquid for release layer 1> Epoxy group-containingsilsesquioxane  90 parts (SQ502-8, Arakawa Chemical Industries, Ltd.)Curing catalyst  8 parts (Celtop(R) CAT-A, Daicel Corporation) Polyesterpolyurethane  2 parts (Vylon UR-1700, TOYOBO Co., Ltd.) Toluene  80parts Methyl ethyl ketone 160 parts

Example 1-7

A thermal transfer sheet of Example 1-7 was obtained exactly in the samemanner as in Example 1-6 except that the coating liquid for releaselayer 1 was replaced by a coating liquid for release layer 2 having thefollowing composition to form the release layer.

<Coating liquid for release layer 2> Epoxy group-containingsilsesquioxane  92 parts (SQ502-8, Arakawa Chemical Industries, Ltd.)Curing catalyst  8 parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 80 parts Methyl ethyl ketone 160 parts

Example 1-8

A thermal transfer sheet of Example 1-8 was obtained exactly in the samemanner as in Example 1-1 except that the coating liquid for protectivelayer 1 was replaced by a coating liquid for protective layer 4 havingthe following composition and the formation conditions for theprotective layer were replaced by the conditions shown in the followingtable 1.

<Coating liquid for protective layer 4> Polyfunctional acrylate  13parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) Urethaneacrylate  13 parts (NK oligomer EA1020, Shin Nakamura Chemical Co.,Ltd.) Urethane acrylate  7 parts (NK ester U-15HA, Shin NakamuraChemical Co., Ltd.) Reactive binder (containing an unsaturated group)  3parts (NK polymer C24T, Shin Nakamura Chemical Co., Ltd.) First filler(volume average particle size: 0.7 μm)  25 parts (XC99-A8808manufactured by Momentive Performance Materials Japan LLC) Second filler(volume average particle size: 12 nm)  34 parts (MEK-AC2140Z, NissanChemical Industries, Ltd.) Surfactant (acrylic surfactant)  1 part(LF-1984, Kusumoto Chemicals, Ltd.) Photo-polymerization initiator  5parts (Irgacure(R) 184, BASF Japan Ltd.) Toluene 100 parts Methyl ethylketone 100 parts

Example 1-9

A thermal transfer sheet of Example 1-9 was obtained exactly in the samemanner as in Example 1-1 except that the coating liquid for protectivelayer 1 was replaced by a coating liquid for protective layer 5 havingthe following composition and the formation conditions for theprotective layer were replaced by the conditions shown in the followingtable 1.

<Coating liquid for protective layer 5> Polyfunctional acrylate  19parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) Urethaneacrylate  19 parts (NK oligomer EA1020, Shin Nakamura Chemical Co.,Ltd.) Urethane acrylate  11 parts (NK ester U-15HA, Shin NakamuraChemical Co., Ltd.) Reactive binder (containing an unsaturated group)  5parts (NK polymer C24T, Shin Nakamura Chemical Co., Ltd.) First filler(volume average particle size: 0.7 μm)  7 parts (XC99-A8808 manufacturedby Momentive Performance Materials Japan LLC) Second filler (volumeaverage particle size: 12 nm)  34 parts (MEK-AC2140Z, Nissan ChemicalIndustries, Ltd.) Surfactant (acrylic surfactant)  1 part (LF-1984,Kusumoto Chemicals, Ltd.) Photo-polymerization initiator  5 parts(Irgacure(R) 184, BASF Japan Ltd.) Toluene 100 parts Methyl ethyl ketone100 parts

Comparative Example 1-1

A thermal transfer sheet of Comparative Example 1-1 was obtained exactlyin the same manner as in Example 1-1 except that the coating liquid forprotective layer 1 was replaced by a coating liquid for protective layerA having the following composition and the formation conditions for theprotective layer were replaced by the conditions shown in the followingtable 1.

<Coating liquid for protective layer A> Polyfunctional acrylate  21parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) Urethaneacrylate  21 parts (NK oligomer EA1020, Shin Nakamura Chemical Co.,Ltd.) Urethane acrylate  12 parts (NK ester U-15HA, Shin NakamuraChemical Co., Ltd.) Reactive binder (containing an unsaturated group)  5parts (NK polymer C24T, Shin Nakamura Chemical Co., Ltd.) Second filler(volume average particle size: 12 nm)  34 parts (MEK-AC2140Z, NissanChemical Industries, Ltd.) Surfactant (acrylic surfactant)  1 part(LF-1984, Kusumoto Chemicals, Ltd.) Photo-polymerization initiator  5parts (Irgacure(R) 184, BASF Japan Ltd.) Toluene 100 parts Methyl ethylketone 100 parts

Comparative Example 1-2

A thermal transfer sheet of Comparative Example 1-2 was obtained exactlyin the same manner as in Example 1-1 except that the coating liquid forprotective layer 1 was replaced by the coating liquid for protectivelayer A having the above composition and the formation conditions forthe protective layer were replaced by the conditions shown in thefollowing table 1.

Comparative Example 1-3

A thermal transfer sheet of Comparative Example 1-3 was obtained exactlyin the same manner as in Example 1-1 except that the coating liquid forprotective layer 1 was replaced by a coating liquid for protective layerB having the following composition and the formation conditions for theprotective layer were replaced by the conditions shown in the followingtable 1.

<Coating liquid for protective layer B> Polyfunctional acrylate  33parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) Urethaneacrylate  33 parts (NK oligomer EA1020, Shin Nakamura Chemical Co.,Ltd.) Urethane acrylate  19 parts (NK ester U-15HA, Shin NakamuraChemical Co., Ltd.) Reactive binder (containing an unsaturated group)  8parts (NK polymer C24T, Shin Nakamura Chemical Co., Ltd.) Surfactant(acrylic surfactant)  1 part (LF-1984, Kusumoto Chemicals, Ltd.)Photo-polymerization initiator  5 parts (Irgacure(R) 184, BASF JapanLtd.) Toluene 100 parts Methyl ethyl ketone 100 parts

Comparative Example 1-4

A thermal transfer sheet of Comparative Example 1-4 was obtained exactlyin the same manner as in Example 1-1 except that the coating liquid forprotective layer 1 was replaced by a coating liquid for protective layerC having the following composition and the formation conditions for theprotective layer were replaced by the conditions shown in the followingtable 1.

<Coating liquid for protective layer C> Polyfunctional acrylate  30parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) Urethaneacrylate  30 parts (NK oligomer EA1020, Shin Nakamura Chemical Co.,Ltd.) Urethane acrylate  17 parts (NK ester U-15HA, Shin NakamuraChemical Co., Ltd.) Reactive binder (containing an unsaturated group)  7parts (NK polymer C24T, Shin Nakamura Chemical Co., Ltd.) First filler(volume average particle size: 0.7 μm)  10 parts (XC99-A8808manufactured by Momentive Performance Materials Japan LLC) Surfactant(acrylic surfactant)  1 part (LF-1984, Kusumoto Chemicals, Ltd.)Photo-polymerization initiator  5 parts (Irgacure(R) 184, BASF JapanLtd.) Toluene 100 parts Methyl ethyl ketone 100 parts

Comparative Example 1-5

A thermal transfer sheet of Comparative Example 1-5 was obtained exactlyin the same manner as in Example 1-1 except that the coating liquid forprotective layer 1 was replaced by a coating liquid for protective layerD having the following composition and the protective layer was formedwithout ultraviolet irradiation.

<Coating liquid for protective layer D> Styrene - acrylic copolymer 150parts (MUTICLE(R) PP320P, Mitsui Chemicals, Inc.) Polyvinyl alcohol 100parts (C-318, DNP Fine Chemicals Co., Ltd.) Water  25 parts Solvent  50parts (Solmix(R) A-11, Japan Alcohol Trading CO., LTD.)

TABLE 1 First UV irradiation Second UV irradiation Total PeakAccumulated Peak Accumulated accumulated Coating liquid for illuminanceexposure illuminance exposure exposure protective layer (mW/cm²)(mJ/cm²) (mW/cm²) (mJ/cm²) (mJ/cm²) Example 1-1 Coating liquid for 49185 1623 136 221 protective layer 1 Example 1-2 Coating liquid for 858113 1623 110 223 protective layer 1 Example 1-3 Coating liquid for 49185 1623 136 221 protective layer 2 Example 1-4 Coating liquid for 491 851623 136 221 protective layer 3 Example 1-5 Coating liquid for 858 220 —— 220 protective layer 1 Example 1-6 Coating liquid for 491 85 1623 136221 protective layer 1 Example 1-7 Coating liquid for 491 85 1623 136221 protective layer 1 Example 1-8 Coating liquid for 491 85 1623 136221 protective layer 4 Example 1-9 Coating liquid for 491 85 1623 136221 protective layer 5 Comparative Coating liquid for 1735 110 1735 110220 Example 1-1 protective layer A Comparative Coating liquid for 491 851623 136 221 Example 1-2 protective layer A Comparative Coating liquidfor 491 85 1623 136 221 Example 1-3 protective layer B ComparativeCoating liquid for 491 85 1623 136 221 Example 1-4 protective layer CComparative Coating liquid for — — — — — Example 1-5 protective layer D

(Measurement of Initial Breakage Peeling-Off Force)

The thermal transfer sheets of Examples 1-1 to 1-9 and ComparativeExamples 1-1 to 1-5 were used to calculate the initial breakagepeeling-off force at a peeling-off temperature of 30° C. and at each ofpeeling-off angles of 60°, 90°, and 120° and the initial breakagepeeling-off force at a peeling-off temperature of 60° C. and at each ofpeeling-off angles of 60°, 90°, and 120°, using the method described in“Method for calculating initial breakage peeling-off force 1” describedabove. The calculation results are shown in Table 2.

(Measurement of Stable-State Peeling-Off Force)

The thermal transfer sheets of Examples 1-1 to 1-9 were used tocalculate the stable-state peeling-off force at each of peeling-offtemperature s of 30° C. and 60° C. and at a peeling-off angle of 90°,using the method described in “Method for calculating stable-statepeeling-off force 1” described above. The calculation results are shownin Table 2.

(Preparation of Transfer Receiving Article)

Onto one face of a white PET (polyethylene terephthalate) film having athickness of 188 μm, a coating liquid for cushion layer having thefollowing composition was applied and then dried. Irradiation with anactive ray using a mercury lamp (300 mJ/cm²) for curing resulted information of a cushion layer having a thickness of 10 μm. Then, gelatinwas applied onto the cushion layer, and then dried to form a barrierlayer having a thickness of 0.7 μm. Then, a coating liquid for receivinglayer having the following composition was coated onto the barrierlayer, and then dried to form a receiving layer having a thickness of2.45 μm. Then, a coating liquid for resin layer having the followingcomposition was applied onto the receiving layer, and then dried to forma resin layer having a thickness of 0.4 μm. Then, under the followingtest printer conditions, using a thermal transfer sheet for imageformation prepared below, a black solid image (image gray scale: 0/255)was formed on the resin layer to obtain a transfer receiving article.

<Coating liquid for cushion layer> Urethane acrylate oligomer  50 parts(NK Oligo UA-160TM, Shin Nakamura Chemical Co., Ltd.) Acrylic acid esterpolymer  30 parts (VANARESIN GH-5270, Shin Nakamura Chemical Co., Ltd.)Urethane acrylate oligomer  18 parts (NK Oligo UA-1280T, Shin NakamuraChemical Co., Ltd.) Polymerization initiator  2 parts (Irgacure(R) 127,BASF Japan Ltd.) Methyl ethyl ketone 100 parts

<Coating liquid for receiving layer> polyvinyl butyral  6 parts(S-LEC(R) BX-1, SEKISUI CHEMICAL CO., LTD.)  4 parts Metalion-containing compound (Ni²⁺[C₇H₁₅COC(COOCH₃)═C (CH₃)O⁻]₂) Methyl ethylketone 80 parts n-Butyl acetate 10 parts

<Coating liquid for resin layer> Polypropylene wax emulsion (solidcontent: 30%) 33 parts (Hitech E433N, TOHO Chemical Industry Co., Ltd.)Water 67 parts

(Preparation of Thermal Transfer Sheet for Image Formation)

Onto a PET (polyethylene terephthalate) film having a thickness of 6 μmsubjected to an easy-adhesive treatment in advance as a substrate, acoating liquid for back face layer having the following composition wasapplied so as to obtain a thickness of 1 μm in the dried state on oneface of the substrate, and then dried to form a back face layer. Then,onto the other face of the substrate, a coating liquid for yellow dyelayer, a coating liquid for magenta dye layer, and a coating liquid forcyan dye layer were each applied so as to obtain a thickness of 1.1 μmin the dried state in a frame-sequential manner, and then the coatingliquids were dried to obtain a thermal transfer sheet for imageformation.

<Coating liquid for back face layer> Polyvinyl butyral   2 parts(S-LEC(R) BX-1, SEKISUI CHEMICAL CO., LTD.) Polyisocyanate curing agent 9.2 parts (BURNOCK(R) D750, DIC Corporation) Phosphoric acid ester  1.3parts (PLYSURF(R) A208S, DKS Co. Ltd.) Talc  0.3 parts (MICRO ACE(R)P-3, Nippon Talc Co., Ltd.) Methyl ethyl ketone 43.6 parts Toluene 43.6parts

<Coating liquid for yellow dye layer> Pigment represented by thefollowing chemical 3 parts formula (Y-1) Polyvinyl acetal 5.5 parts(S-LEC (R) KS-5, SEKISUI CHEMICAL CO., LTD.) Epoxy-modified acryl resin1 part (RESEDA (R) GP-305, Toagosei Co., Ltd.) Urethane-modifiedsilicone oil 0.5 parts (DAIALLOMER (R) SP2105, Dainichiseika Color &Chemicals Mfg. Co., Ltd.) Methyl ethyl ketone 80 parts Toluene 10 parts[Formula 2]

<Coating liquid for magenta dye layer> Pigment represented by thefollowing chemical 3 parts formula (M-1) Polyvinyl acetal 5.5 parts(S-LEC (R) KS-5, SEKISUI CHEMICAL CO., LTD.) Epoxy-modified acryl resin1 part (RESEDA (R) GP-305, Toagosei Co., Ltd.) Urethane-modifiedsilicone oil 0.5 parts (DAIALLOMER (R) SP2105, Dainichiseika Color &Chemicals Mfg. Co., Ltd.) Methyl ethyl ketone 80 parts Toluene 10 parts[Formula 3]

<Coating liquid for cyan dye layer> Pigment represented by the followingchemical 3 parts formula (C-1) Polyvinyl acetal 5.5 parts (S-LEC (R)KS-5, SEKISUI CHEMICAL CO., LTD.) Epoxy-modified acryl resin 1 part(RESEDA (R) GP-305, Toagosei Co., Ltd.) Urethane-modified silicone oil0.5 parts (DAIALLOMER (R) SP2105, Dainichiseika Color & Chemicals Mfg.Co., Ltd.) Methyl ethyl ketone 80 parts Toluene 10 parts [Formula 4]

(Test Printer Conditions)

Thermal head: KEE-57-12GAN2-STA (KYOCERA Corporation)

Printing voltage: 25.5 (V)

Heater average resistance: 5545 (Ω)

Main scanning direction printing density: 300 (dpi)

Sub scanning direction printing density: 300 (dpi)

Line cycle: 2 (msec./line)

Printing start temperature: 30 (° C.)

(Preparation of Print)

The transfer receiving article prepared by the above method and thethermal transfer sheet of each of Examples 1-1 to 1-9 and ComparativeExamples 1-1 to 1-5 were superposed on each other such that the resinlayer of the transfer receiving article was in contact with the transferlayer of the thermal transfer sheet. A laminator (GL835PRO, Japan GBC)was used under conditions of upper and lower roll temperatures of 150°C., a lamination speed of 15.07 mm/sec., and a roll nip width of 1 mm tolaminate the thermal transfer sheet of each of Examples and ComparativeExamples onto the transfer receiving article. The transfer layer waspeeled from the thermal transfer sheet laminated onto the transferreceiving article such that only the transfer layer remained on the sideof the transfer receiving article to thereby prepare a print of each ofExamples 1-1 to 1-9 and Comparative Examples 1-1 to 1-5, in which printthe transfer layer of the thermal transfer sheet of each of Examples andComparative Example was transferred onto the transfer receiving article.

(Measurement of Scratch Hardness)

The scratch hardness of the surface of each print of Examples 1-1 to 1-9and Comparative Examples 1-1 to 1-5 prepared by the above method wasmeasured by a method in compliance with JIS-K-5600-5-5 (a sapphireneedle having a tip radius of 0.1 mm was used). The measurement resultsare shown in Table 2.

(Durability Evaluation)

The durability of the surface of each print of Examples 1-1 to 1-9 andComparative Examples 1-1 to 1-5 prepared by the above method wasconducted in compliance with ANSI-INCITS 322-2002, 5.9 Surface Abrasionby a Taber abrasion tester (No. 410, Toyo Seiki Seisaku-sho, Ltd.). Thereflection density of an abraded portion was measured every 250 cyclesby a spectrophotometer RD918 (X-Rite Inc., visual filter used). When thereflection density decreased to less than 50% based on the densitybefore abrasion, abrasion was finished, and the durability was evaluatedbased on the following evaluation criteria. The evaluation results areshown in Table 2.

“Evaluation Criteria”

A: The number of cycles when the reflection density decreased to lessthan 50% is 2000 or more.

B: The number of cycles when the reflection density decreased to lessthan 50% is 1000 or more and less than 2000.

NG: The number of cycles when the reflection density decreased to lessthan 50% is less than 1000.

(Transferability Evaluation (Head Untransfer Evaluation))

The transfer layer of the thermal transfer sheet of each of Examples 1-1to 1-9 and Comparative Examples 1-1 to 1-5 was fused on the transferreceiving article produced above using a heat roller of which surfacetemperature was set to 200° C. This transfer layer was peeled from theside of the substrate of the thermal transfer sheet using a peel roll(diameter: 5 mm) to obtain a print of each of Examples 1-1 to 1-9 andComparative Examples 1-1 to 1-5, in which print the transfer layer ofthe thermal transfer sheet of each of Examples and Comparative Exampleswas transferred on the transfer receiving article. The peeling-off angleduring peel using a peel roll was 600 and 90°, and the peel wasconducted both at peeling-off temperatures of 30° C. and 60° C. Both thetransfer rate and the peel rate were set to 1464 mm/min. The peeling-offtemperature is a value determined by contactlessly measuring the surfaceof the transfer layer located in proximity the peel roll using aradiation thermometer.

“Evaluation Criteria”

A: An untransferred portion onto the transfer receiving article occursat less than 0.5 mm from the transfer start end of the transfer layer.

B: An untransferred portion onto the transfer receiving article occursat 0.5 mm or more and less than 1 mm from the transfer start end of thetransfer layer.

NG: An untransferred portion onto the transfer receiving article occursat 1 mm or more from the transfer start end of the transfer layer.

(Foil Cutting Property Evaluation (Tailing Evaluation))

The length of tailing in the rear end portion of the print obtained inthe above evaluation of the transferability evaluation (head untransfer)was measured, and the tailing was evaluated based on the followingevaluation criteria. The evaluation results are shown in Table 2. Notethat the results of the foil cutting property evaluation are the sameresults irrespective of the peeling-off temperature and windingdiameter.

“Evaluation Criteria”

A: The length of tailing is less than 0.5 mm.

B: The length of tailing is 0.5 mm or more and less than 1 mm.

NG: The length of tailing is 1 mm or more.

TABLE 2 Stable-state peeling-off force Foil Initial breakage peeling-offforce (mN/m) (mN/m) Scratch Transferability cutting 30° C. 60° C. 30° C.60° C. hardness 30° C. 60° C. property 60° 90° 120° 60° 90° 120° 90° 90°(g) Durability 60° 90° 60° 90° (tailing) Example 1-1 0.715 0.311 0.2161.237 0.343 0.226 0.245 0.221 250 A A A A A B Example 1-2 0.736 0.2880.184 1.166 0.386 0.173 0.236 0.221 250 A A A A A B Example 1-3 1.3430.692 0.188 1.770 0.775 0.201 0.265 0.235 250 A B A B A B Example 1-40.664 0.228 0.115 1.053 0.353 0.112 0.216 0.206 230 A A A A A B Example1-5 0.922 0.304 0.196 1.461 0.402 0.196 0.235 0.216 250 A A A B A BExample 1-6 1.105 0.489 0.214 1.261 0.719 0.280 0.315 0.294 250 A A A AA A Example 1-7 0.686 0.284 0.196 1.138 0.324 0.216 0.216 0.196 250 A AA A A B Example 1-8 0.500 0.177 0.098 0.883 0.294 0.098 0.167 0.157 180B A A A A B Example 1-9 1.098 0.520 0.196 1.500 0.588 0.186 0.255 0.245250 A B A B A B Comparative 4.566 2.033 0.671 5.448 2.410 1.401 — — 300A NG NG NG NG — Example 1-1 Comparative 3.863 0.744 0.369 4.534 1.1600.147 — — 280 A NG B NG NG — Example 1-2 Comparative 12.455 6.700 3.71714.034 8.954 5.286 — — 250 A NG NG NG NG — Example 1-3 Comparative 6.2763.099 2.324 8.356 5.502 3.609 — — 230 A B B NG NG — Example 1-4Comparative 1.167 0.785 0.510 1.236 0.932 0.716 — — 130 NG A A A A —Example 1-5

Example 2-1

As a substrate, a PET (polyethylene terephthalate) film having athickness of 25 μm was used. The coating liquid for peel layer havingthe above composition was applied onto one face of this substrate, andthen dried to form a peel layer having a thickness of 0.5 μm.Subsequently, onto the peel layer, a coating liquid for protective layer6 having the following composition was applied and then dried. Then, aUV exposure machine (Fusion UV, F600V, LH10 lamp, H valve, cold-typereflector) was used to apply ultraviolet irradiation (exposure (220mJ/cm²)) to form a protective layer having a thickness of 4.5 μm. Then,the coating liquid for primer layer 1 having the above composition wasapplied onto the protective layer, and then dried to form a primer layerhaving a thickness of 0.8 μm. Then, the coating liquid for adhesivelayer having the above composition was applied onto the primer layer,and then dried to form an adhesive layer having a thickness of 0.6 μm.Thus, a thermal transfer sheet of Example 2-1 was obtained, in which thetransfer layer was provided on one face of the substrate. Note that thetransfer layer of the thermal transfer sheet of Example 2-1 has alayered structure in which the peel layer, the protective layer, theprimer layer, and the adhesive layer are layered in this order from theside of the substrate.

<Coating liquid for protective layer 6> Polyfunctional acrylate  20parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) Urethaneacrylate  20 parts (NK oligomer EA1020, Shin Nakamura Chemical Co.,Ltd.) Urethane acrylate  10 parts (NK ester U-15HA, Shin NakamuraChemical Co., Ltd.) Reactive binder (containing an unsaturated group)  5parts (NK polymer C24T, Shin Nakamura Chemical Co., Ltd.) Filler (volumeaverage particle size: 12 nm)  40 parts (MEK-AC2140Z, Nissan ChemicalIndustries, Ltd.) Surfactant (acrylic surfactant)  0.1 part (LF-1984,Kusumoto Chemicals, Ltd.) Toluene 200 parts Methyl ethyl ketone 200parts

Example 2-2

As a substrate, a PET (polyethylene terephthalate) film having athickness of 25 μm was used. A coating liquid for primer layer 2 havingthe following composition was applied onto one face of this substrate,and then dried to form a primer layer having a thickness of 0.5 μm.Then, a coating liquid for release layer 3 having the followingcomposition was applied onto the primer layer, and then dried to form arelease layer having a thickness of 0.6 μm. Subsequently, onto therelease layer, the coating liquid for protective layer 6 having theabove composition was applied and then dried. Then, a UV exposuremachine (Fusion UV, F600V, LH10 lamp, H valve, cold-type reflector) wasused to apply ultraviolet irradiation (exposure (220 mJ/cm²)) to form aprotective layer having a thickness of 4.5 μm. Then, the coating liquidfor primer layer 1 having the above composition was applied onto theprotective layer, and then dried to form a primer layer having athickness of 0.8 μm. Then, the coating liquid for adhesive layer havingthe above composition was applied onto the primer layer, and then driedto form an adhesive layer having a thickness of 0.6 μm. Thus, a thermaltransfer sheet of Example 2-2 was obtained, in which the transfer layerwas provided on one face of the substrate. Note that the transfer layerof the thermal transfer sheet of Example 2-2 has a layered structure inwhich the protective layer, the primer layer, and the adhesive layer arelayered in this order from the side of the substrate.

<Coating liquid for primer layer 2> Aqueous polyurethane  82 parts(HYDRAN(R) AP-40N, DIC Corporation) Epoxy resin  18 parts (WATERSOL(R)WSA-950, DIC Corporation) Water 450 parts Solvent 450 parts (Solmix(R)A-11, Japan Alcohol Trading CO., LTD.)

<Coating liquid for release layer 3> Epoxy group-containingsilsesquioxane  90 parts (SQ502-8, Arakawa Chemical Industries, Ltd.)Curing catalyst  8 parts (Celtop(R) CAT-A, Daicel Corporation) Siliconeresin filler (average particle size: 6.0 μm)  2 parts (Tospearl(R)2000B, Momentive Performance Materials Japan LLC) Toluene  80 partsMethyl ethyl ketone 160 parts

Example 2-3

A thermal transfer sheet of Example 2-3 was obtained exactly in the samemanner as in Example 2-2 except that the coating liquid for releaselayer 3 was replaced by a coating liquid for release layer 4 having thefollowing composition to form the release layer.

<Coating liquid for release layer 4> Epoxy group-containingsilsesquioxane 91.2 parts (SQ502-8, Arakawa Chemical Industries, Ltd.)Curing catalyst  8.2 parts (Celtop(R) CAT-A, Daicel Corporation)Silicone resin filler (average particle size: 3.0 μm)  0.6 parts(Tospearl(R) 130, Momentive Performance Materials Japan LLC) Toluene  80 parts Methyl ethyl ketone  160 parts

Comparative Example 2-1

A thermal transfer sheet of Comparative Example 2-1 was obtained exactlyin the same manner as in Example 2-2 except that the coating liquid forprotective layer 6 was replaced by the coating liquid for protectivelayer D having the above composition to form the protective layer.

Comparative Example 2-2

A thermal transfer sheet of Comparative Example 2-2 was obtained exactlyin the same manner as in Example 2-2 except that the coating liquid forrelease layer 3 was replaced by a coating liquid for release layer Ahaving the following composition to form the release layer.

<Coating liquid for release layer A> Epoxy group-containingsilsesquioxane 91.3 parts (SQ502-8, Arakawa Chemical Industries, Ltd.)Curing catalyst  8.4 parts (Celtop(R) CAT-A, Daicel Corporation)Silicone resin filler (average particle size: 0.7 μm)  0.3 parts(X-52-854, Shin-Etsu Chemical Co., Ltd.) Toluene   80 parts Methyl ethylketone  160 parts

(Measurement of Surface Roughness (SRa))

With respect to the thermal transfer sheets of Examples 2-1 and 2-2 andComparative Example 2-2, when these thermal transfer sheets areobtained, in the stage before the protective layer was formed on therelease layer, the surface roughness (SRa) of the surface of the releaselayer was measured using a three-dimensional surface roughness shapemeasuring apparatus (SURFCOM® 1400, TOKYO SEIMITSU CO., LTD.). Themeasurement results are shown in Table 3.

(Measurement of Initial Breakage Peeling-Off Force)

The thermal transfer sheet of each of Examples and Comparative Exampleswas cut into a width of 65 mm. The cut thermal transfer sheet of each ofExamples and Comparative Examples was bonded, using transparentdouble-sided tape (NICETACK® NW-15, Nichiban Co., Ltd.), onto a hotstage (HP2000, Shinto Scientific Co., Ltd.) of which temperature isadjusted to 20° C. such that the surface of the hot stage was opposed tothe surface of the transfer layer. In the state where the temperature ofthe thermal transfer sheet was kept at 20° C., the transfer layer of thethermal transfer sheet bonded was peeled from the side of the substrateof the thermal transfer sheet under conditions of a peeling-off angle of90° and a peel rate of 5 mm/sec, while the peeling-off force in therange from the initial peeling-off portion (see FIG. 7) as the startpoint to a point 5 mm (5 mm exclusive) distant from the start point wassequentially measured with a peeling-off force measurement device(Digital Force Gauge DPX-5, IMADA CO., LTD.). The value of the maximumpeeling-off force in this measurement range was divided by the width ofthe thermal transfer sheet (65 mm) to calculate the initial breakagepeeling-off force. The initial breakage peeling-off forces at 30° C. and40° C. were calculated in the same manner. The calculation results ofthe initial breakage peeling-off force are shown in Table 1. Note thatthe above transparent double-sided tape bonds the hot stage and thethermal transfer sheet over a range of 15 mm from the initialpeeling-off portion (see FIG. 7) as the start point in the peel-offdirection.

(Measurement of Scratch Hardness)

The transfer receiving article prepared by the above method and thethermal transfer sheet of each of Examples 2-1 to 2-3 and ComparativeExamples 2-1 and 2-2 were superposed on each other such that the resinlayer of the transfer receiving article was in contact with the transferlayer of the thermal transfer sheet, and prints of Examples 2-1 to 2-3and Comparative Examples 2-1 and 2-2 were prepared in the same manner asin Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-5 describedabove. The scratch hardness of the surface of each print of Examples andComparative Examples prepared was measured by a method in compliancewith JIS-K-5600-5-5 (a sapphire needle having a tip radius of 0.1 mm wasused). The measurement results are shown in Table 3.

(Durability Evaluation)

Prints of Examples 2-1 to 2-3 and Comparative Examples 2-1 and 2-2 wereprepared in the same manner as in Examples 1-1 to 1-9 and ComparativeExamples 1-1 to 1-5 described above. The durability of the surface ofthe prepared print of each of Examples and Comparative Examples wasmeasured in the same manner as in Examples 1-1 to 1-9 and ComparativeExamples 1-1 to 1-5 described above, and the durability was evaluatedbased on evaluation criteria similar to those of Examples 1-1 to 1-9 andComparative Examples 1-1 to 1-5 described above. The evaluation resultsare shown in Table 3.

(Transferability Evaluation (Head Untransfer Evaluation))

Prints of Examples 2-1 to 2-3 and Comparative Examples 2-1 and 2-2 wereprepared in the same manner as in Examples 1-1 to 1-9 and ComparativeExamples 1-1 to 1-5 described above. The situation of transfer of thetransfer layer onto the transfer receiving article in the prepared printof each of Examples and Comparative Examples was checked, andtransferability evaluation (head untransfer evaluation) was conductedbased on the following evaluation criteria. The evaluation results areshown in Table 3.

“Evaluation Criteria”

A: An untransferred portion onto the transfer receiving article occursat less than 0.5 mm from the transfer start end of the transfer layer.

B: An untransferred portion onto the transfer receiving article occursat 0.5 mm or more and less than 1 mm from the transfer start end of thetransfer layer.

NG: An untransferred portion onto the transfer receiving article occursat 1 mm or more from the transfer start end of the transfer layer.

(Measurement of Glossiness)

Prints of Examples 2-1 to 2-3 and Comparative Examples 2-1 and 2-2 wereprepared in the same manner as in Examples 1-1 to 1-9 and ComparativeExamples 1-1 to 1-5 described above. The glossiness of the surface ofthe prepared print of each of Examples and Comparative Examples wasmeasured using a glossiness meter (VG2000, Nippon Denshoku IndustriesCo. Ltd.) (measurement angle: 20°). The measurement results are shown inTable 3.

TABLE 3 Surface Initial breakage peeling-off force Scratch roughness(mN/m) hardness SRa (μm) 20° C. 30° C. 40° C. (g) DurabilityTransferability Glossiness Example 2-1 — 4.12 4.41 4.71 280 A B 83Example 2-2 0.091 1.77 1.96 2.16 300 A A 42 Example 2-3 0.064 3.24 3.433.73 300 A A 66 Comparative — 0.78 0.98 1.18 130 NG A 83 Example 2-1Comparative 0.046 5.98 6.37 6.86 300 A NG 78 Example 2-2

Example 3-1

Using a polyethylene terephthalate (PET) film having a thickness of 12μm as a substrate, a coating liquid for anchor coat layer having thefollowing composition was applied onto one face of the substrate so asto obtain a thickness of 0.5 μm in the dried state, and then dried toform an anchor coat layer. A coating liquid for release layer 5 havingthe following composition was applied onto the anchor coat layer so asto obtain a thickness of 0.7 μm in the dried state, and then dried andmatured in an oven at 60° C. for 84 hours to form a release layer. Ontothe release layer, a coating liquid for protective layer 7 having thefollowing composition was applied and then dried. Then, exposure(exposure (220 mJ/cm²)) using a UV exposure machine so as to obtain athickness of 4.5 μm after the exposure resulted in formation of aprotective layer. Thus, a thermal transfer sheet of Example 3-1 wasobtained in which the anchor coat layer, the release layer, and theprotective layer as the transfer layer were layered in this order fromthe side of the substrate. Note that the UV exposure machine used was anoutput adjustable-type UV lamp system (DRS-10/12QN, Fusion UV SystemsJapan K.K.).

<Coating liquid for anchor coat layer> Polyurethane (solid content: 35%)7.2 parts (AP-40N, DIC Corporation) Epoxy-type curing agent 0.5 parts(WATERSOL(R) WSA-950, DIC Corporation) Solvent 9.8 parts (Solmix(R)A-11, Japan Alcohol Trading CO., LTD.) Water 2.4 parts

<Coating liquid for release layer 5> Epoxy group-containingsilsesquioxane (solid content: 72.6%) 5.8 parts (SQ502-8, ArakawaChemical Industries, Ltd.) Aluminum catalyst (solid content: 10%) 3.8parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 3.5 parts Methylethyl ketone 6.9 parts

<Coating liquid for protective layer 7> Trifunctional acrylate  1.4parts (NK ester A-9300, Shin Nakamura Chemical Co., Ltd.) BisphenolA-type epoxy acrylate  1.4 parts (NK oligomer EA-1020, Shin NakamuraChemical Co., Ltd.) Pentadeca-functional urethane acrylate  1.4 parts(NK ester U-15HA, Shin Nakamura Chemical Co., Ltd.) Polymer acrylate(solid content: 50%)  0.7 parts (NK ester C-24T, Shin Nakamura ChemicalCo., Ltd.) Filler (silica) (average particle size: 12 nm) (solidcontent:  5.9 parts 50%) (MEK-AC2140Z, Nissan Chemical Industries, Ltd.)Photo-polymerization initiator 0.14 parts (Irgacure(R) 184, BASF JapanLtd.) Surface adjusting agent (solid content: 50%) 0.14 parts (LF1984,Kusumoto Chemicals, Ltd.) Toluene  4.8 parts Methyl ethyl ketone  9.5parts

Example 3-2

A thermal transfer sheet of Example 3-2 was obtained exactly in the samemanner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 6 having thefollowing composition to form the release layer.

<Coating liquid for release layer 6> Epoxy group-containingsilsesquioxane 5.8 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Aluminum catalyst (solid content: 10%) 3.8parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 3.4 parts Methylethyl ketone 6.8 parts Water 0.2 parts

Example 3-3

A thermal transfer sheet of Example 3-3 was obtained exactly in the samemanner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 7 having thefollowing composition to form the release layer.

<Coating liquid for release layer 7> Epoxy group-containingsilsesquioxane 5.8 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Aluminum catalyst (solid content: 10%) 3.8parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 3.3 parts Methylethyl ketone 6.6 parts Water 0.5 parts

Example 3-4

A thermal transfer sheet of Example 3-4 was obtained exactly in the samemanner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 8 having thefollowing composition to form the release layer.

<Coating liquid for release layer 8> Epoxy group-containingsilsesquioxane 5.8 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Aluminum catalyst (solid content: 10%) 3.8parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 3.2 parts Methylethyl ketone 6.4 parts Water 0.8 parts

Example 3-5

A thermal transfer sheet of Example 3-5 was obtained exactly in the samemanner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 9 having thefollowing composition to form the release layer.

<Coating liquid for release layer 9> Epoxy group-containingsilsesquioxane 5.8 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Aluminum catalyst (solid content: 10%) 3.8parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 3.1 parts Methylethyl ketone 6.2 parts Water 1.1 parts

Example 3-6

A thermal transfer sheet of Example 3-6 was obtained exactly in the samemanner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 10 having thefollowing composition to form the release layer.

<Coating liquid for release layer 10> Epoxy group-containingsilsesquioxane 5.6 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Polyester (acid value <2 mgKOH/g) 0.1 parts(Vylon(R) 226, TOYOBO CO., LTD.) Aluminum catalyst (solid content: 10%)3.8 parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 3.2 parts Methylethyl ketone 6.4 parts Water 0.8 parts

Example 3-7

A thermal transfer sheet of Example 3-7 was obtained exactly in the samemanner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 11 having thefollowing composition to form the release layer.

<Coating liquid for release layer 11> Epoxy group-containingsilsesquioxane 5.6 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Urethane-modified polyester (solid content:30%) 0.1 parts (acid value: 26 mgKOH/g) (Vylon(R) UR-1700, TOYOBO Co.,Ltd.) Aluminum catalyst (solid content: 10%) 3.8 parts (Celtop(R) CAT-A,Daicel Corporation) Toluene 3.2 parts Methyl ethyl ketone 6.4 partsWater 0.8 parts

Example 3-8

A thermal transfer sheet of Example 3-8 was obtained exactly in the samemanner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 12 having thefollowing composition to form the release layer.

<Coating liquid for release layer 12> Epoxy group-containingsilsesquioxane 1.1 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Urethane-modified polyester (solid content:40%) 8.2 parts (acid value: 35 mgKOH/g) (Vylon(R) UR-3500, TOYOBO Co.,Ltd.) Zirconia catalyst (solid content: 45%) 1.1 parts (ZC-540,Matsumoto Fine Chemical Co. Ltd.) Acetyl acetone 3.1 parts Toluene 2.2parts Methyl ethyl ketone 4.3 parts

Example 3-9

A thermal transfer sheet of Example 3-9 was obtained exactly in the samemanner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 13 having thefollowing composition to form the release layer.

<Coating liquid for release layer 13> Epoxy group-containingsilsesquioxane 1.1 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Urethane-modified polyester (solid content:40%) 8.2 parts (acid value: 35 mgKOH/g) (Vylon(R) UR-3500, TOYOBO Co.,Ltd.) Zirconia catalyst (solid content: 45%) 1.1 parts (ZC-540,Matsumoto Fine Chemical Co. Ltd.) Acetyl acetone 3.1 parts Toluene 2.1parts Methyl ethyl ketone 4.2 parts Water 0.2 parts

Example 3-10

A thermal transfer sheet of Example 3-10 was obtained exactly in thesame manner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 14 having thefollowing composition to form the release layer.

<Coating liquid for release layer 14> Epoxy group-containingsilsesquioxane 1.1 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Urethane-modified polyester (solid content:40%) 8.2 parts (acid value: 35 mgKOH/g) (Vylon(R) UR-3500, TOYOBO Co.,Ltd.) Zirconia catalyst (solid content: 45%) 1.1 parts (ZC-540,Matsumoto Fine Chemical Co. Ltd.) Acetyl acetone 3.1 parts Toluene   2parts Methyl ethyl ketone   4 parts Water 0.5 parts

Example 3-11

A thermal transfer sheet of Example 3-11 was obtained exactly in thesame manner as in Example 3-1 except that the coating liquid for releaselayer 5 was replaced by a coating liquid for release layer 15 having thefollowing composition to form the release layer.

<Coating liquid for release layer 15> Epoxy group-containingsilsesquioxane 1.1 parts (solid content: 72.6%) (SQ502-8, ArakawaChemical Industries, Ltd.) Urethane-modified polyester (solid content:40%) 8.2 parts (acid value: 35 mgKOH/g) (Vylon(R) UR-3500, TOYOBO Co.,Ltd.) Zirconia catalyst (solid content: 45%) 1.1 parts (ZC-540,Matsumoto Fine Chemical Co. Ltd.) Acetyl acetone 3.1 parts Toluene 1.9parts Methyl ethyl ketone 3.8 parts Water 0.8 parts

Comparative Example 3-1

A thermal transfer sheet of Comparative Example 3-1 was obtained exactlyin the same manner as in Example 3-1 except that the coating liquid forrelease layer 5 was replaced by a coating liquid for release layer Bhaving the following composition to form the release layer.

<Coating liquid for release layer B> Epoxy group-containingsilicone-modified 8.4 parts acryl resin (solid content: 50%) (Celtop(R)226, Daicel Corporation) Aluminum catalyst (solid content: 10%) 3.8parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 2.6 parts Methylethyl ketone 5.2 parts

Comparative Example 3-2

A thermal transfer sheet of Comparative Example 3-2 was obtained exactlyin the same manner as in Example 3-1 except that the coating liquid forrelease layer 5 was replaced by a coating liquid for release layer Chaving the following composition to form the release layer.

<Coating liquid for release layer C> Epoxy group-containingsilicone-modified 8.4 parts acryl resin (solid content: 50%) (Celtop(R)226, Daicel Corporation) Aluminum catalyst (solid content: 10%) 3.8parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 2.5 parts Methylethyl ketone 5.1 parts Water 0.2 parts

Comparative Example 3-3

A thermal transfer sheet of Comparative Example 3-3 was obtained exactlyin the same manner as in Example 3-1 except that the coating liquid forrelease layer 5 was replaced by a coating liquid for release layer Dhaving the following composition to form the release layer.

<Coating liquid for release layer D> Epoxy group-containingsilicone-modified 8.4 parts acryl resin (solid content: 50%) (Celtop(R)226, Daicel Corporation) Aluminum catalyst (solid content: 10%) 3.8parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 2.4 parts Methylethyl ketone 4.8 parts Water 0.5 parts

Comparative Example 3-4

A thermal transfer sheet of Comparative Example 3-4 was obtained exactlyin the same manner as in Example 3-1 except that the coating liquid forrelease layer 5 was replaced by a coating liquid for release layer Ehaving the following composition to form the release layer.

<Coating liquid for release layer E> Epoxy group-containingsilicone-modified 8.4 parts acryl resin (solid content: 50%) (Celtop(R)226, Daicel Corporation) Aluminum catalyst (solid content: 10%) 3.8parts (Celtop(R) CAT-A, Daicel Corporation) Toluene 2.3 parts Methylethyl ketone 4.6 parts Water 0.8 parts

(Stability Evaluation of Coating Liquid)

The coating liquids for release layer 6 to 11 and 13 to 15 and thecoating liquids for release layer C to E were each prepared, stirredwith a stirrer for five minutes, and then left to stand for fiveminutes. While water was removed from the formulation of the coatingliquids for release layer 6 to 11 and 13 to 15 and the coating liquidsfor release layer C to E, and the coating liquids were separatelyprepared. Each coating liquid was stirred with a stirrer for fiveminutes, and then left to stand for five minutes. Each coating liquidafter standing was visually checked. The state of the coating liquid dueto presence or absence of addition of water was visually checked, andthe stability of the coating liquid due to presence or absence ofaddition of water was evaluated based on the following evaluationcriteria. Note that the coating liquids for release layer 6 to 11 and 13to 15 and the coating liquids for release layer C to E respectivelycorrespond to Examples 3-2 to 3-7 and 3-9 to 3-11 and ComparativeExamples 3-2 to 3-4.

<Evaluation Criteria>

A: No change is caused by addition of water.

B: The state of the coating liquid is slightly changed by addition ofwater.

NG: The state of the coating liquid is markedly changed by addition ofwater.

(Solvent Resistance Evaluation)

In formation of the thermal transfer sheet of each of Examples andComparative Examples, after formation of the release layer, the surfaceof the release layer was rubbed once with a cotton swab immersed in asolution prepared by mixing methyl ethyl ketone (MEK) and toluene at amass ratio of 2:1. Then, the surface of the release layer was visuallychecked, and the solvent resistance was evaluated based on the followingevaluation criteria. The evaluation results are shown in Table 4.

<Evaluation Criteria>

A: No damage of the surface of the release layer is observed.

B: Slight damage is observed on the release layer, but there is noproblem in practical use.

NG: Observed is damage on the release layer, which results in a problemin practical uses.

(Peel Stability Evaluation (Evaluation of Performance Variation inReleasability))

In order to measure the initial breakage peeling-off force five times,five pieces of transparent double-sided tape (NICETACK® NW-15) cut outto a size of 80 mm in length in the width direction and 15 mm in lengthin the peel-off direction were provided as shown in FIG. 10A. Then, thefive pieces of the transparent double-sided tape provided were affixedonto a hot stage (HP2000, Shinto Scientific Co., Ltd.) of whichtemperature was adjusted to 70° C., at intervals of 7.5 mm in thepeel-off direction. Then, as shown in FIG. 10B, the thermal transfersheet of Example 3-1 shaped to a size of 65 mm in length in the widthdirection and 80 mm in length in the peel-off direction was superposedon the five pieces of the transparent double-sided tape so as to coverthe pieces together to bond the transparent double-sided tape and thethermal transfer sheet of Example 3-1 to each other. The transparentdouble-sided tape and the thermal transfer sheet of Example 3-1 werebonded to each other such that the transparent double-sided tape was incontact with the transfer layer. In FIG. 10B, the regions of the thermaltransfer sheet superposed on the transparent double-sided tape areregions of the transfer layer to be peeled (first to fifth portionssurrounded by dotted lines). Then, in a state where the thermal transfersheet of Example 3-1 was kept at 70° C., the thermal transfer sheetportion not superposed on the transparent double-sided tape was bent at90°, at the boundary at the upstream end in the peel-off direction ofthe transparent double-sided tape as the start point, as shown in FIG.11A. The transfer layer was peeled under conditions of a peeling-offangle of 90° against the face of the hot stage and a peel rate of 5mm/sec. such that only the transfer layer remained on the transparentdouble-sided tape, as shown in FIG. 11B. The peeling-off force in therange from the upstream end in the peel-off direction of the transparentdouble-sided tape as the start point, at which peel was started, to apoint 5 mm distant toward the downstream of the peel-off direction (0 mmto 5 mm when the start point at which peel is started was set to 0 mm)was measured with a digital force gauge (Digital Force Gauge ZTA-5N,IMADA CO., LTD.), and the value of the maximum peeling-off force in thismeasurement range was taken as the initial breakage peeling-off force.This measurement was conducted on each region to be peeled (first tofifth portions surrounded by dotted lines), and the standard deviationof the initial breakage peeling-off force measured by the above method(the standard deviation of the initial breakage peeling-off forcemeasured at each region to be peeled) was calculated, and the peelstability was evaluated. The standard deviation for the thermal transfersheets of Examples 3-2 to 3-11 and Comparative Example 3-1 to 3-4 wascalculated in the same manner as for the thermal transfer sheet ofExample 3-1. The standard deviation of the peeling-off force calculatedand the evaluation results of the peel stability based on the followingevaluation criteria are shown in Table 4. With a smaller standarddeviation, a release layer having no variation in the performance can beformed. Additionally, the above peel was conducted on the thermaltransfer sheet of each of Examples and Comparative Examples in the rangefrom the start point, at which peel was started, to a point 15 mmdistant in the peel-off direction, which point was the rear end of thelength in the peel-off direction of the transparent double-sided tape (0mm to 15 mm), that is, in the range from the upstream end in thepeel-off direction of the transparent double-sided tape to thedownstream end in the peel-off direction thereof, and the evaluation oftailing described below was conducted (see FIG. 11C). Note that peel inthe range from a point 5 mm distant from the upstream end in thepeel-off direction of the transparent double-sided tape as the startpoint to a point 15 mm distant from the start point (5 mm to 15 mm) wasconducted using a fan-type tension gauge (deflection to one side: 50 gO-KT 0.5N, Oba Keiki Seisakusho Co., Ltd.) instead of the above digitalforce gauge (Digital Force Gauge ZTA-5N, IMADA CO., LTD.). FIG. 11C is aview for explaining the length of tailing, illustrating the state of thetransfer layer remaining on the transparent double-sided tape after thepeel of the regions to be peeled was finished.

<Evaluation Criteria>

A: The standard deviation of the peeling-off force is less than 2.

B: The standard deviation of the peeling-off force is 2 or more and lessthan 5.

NG: The standard deviation of the peeling-off force is 5 or more.

(Tailing Evaluation (Releasability Evaluation))

After peel conducted on each region to be peeled described above in therange from the upstream end in the peel-off direction of the transparentdouble-sided tape to the downstream end in the peel-off directionthereof (peel in the range from 0 mm to 15 mm), the transfer layerremaining on the hot stage side was visually checked, and the tailingwas evaluated based on the following evaluation criteria. The evaluationof the tailing is based on the average of the above five tailing length.The evaluation results are shown in Table 4. The length of tailingmeans, when the transfer layer is transferred onto the transferreceiving article (transparent double-sided tape), the length of thetransfer layer transferred so as to protrude to a non-transfer regionside not superposed on the transparent double-sided tape from a boundarybetween a transfer region and the non-transfer region of the transferlayer (downstream end in the peel-off direction of the transparentdouble-sided tape as the rear end of the peel) as the start point (seeFIG. 11C). The more satisfactory the releasability of the transferlayer, the shorter the tailing. That is, the transfer layer remainsalong the shape superposed on the transparent double-sided tape.

<Evaluation Criteria>

A: The length of tailing is 1 mm or less.

B: The length of tailing is more than 1 mm and 2 mm or less.

C: The length of tailing is more than 2 mm.

TABLE 4 peel stability Stability of Solvent Standard coating liquidresistance deviation Evaluation Tailing Example 3-1 Not evaluated A 0.6A C Example 3-2 A A 1.2 A C Example 3-3 A A 1.9 A C Example 3-4 A A 1.9A C Example 3-5 B B 2.2 B C Example 3-6 A NG 1.7 A B Example 3-7 A A 4.2B B Example 3-8 Not evaluated A 1.9 A B Example 3-9 A A 2.0 B A Example3-10 A A 0.8 A A Example 3-11 A A 2.2 B A Comparative Not evaluated A14.4 NG — Example 3-1 Comparative A A 18.4 NG — Example 3-2 ComparativeB B 20.2 NG — Example 3-3 Comparative NG NG 23.0 NG — Example 3-4

REFERENCE SIGNS LIST

-   -   1 Substrate    -   2 Release layer    -   3 Protective layer    -   4 peel layer    -   5 Adhesive layer    -   7 Adhesion layer    -   10 Transfer layer    -   100 Thermal transfer sheet    -   50 Transfer receiving article    -   60 Print

1. A thermal transfer sheet having a substrate, and a transfer layerprovided on the substrate, wherein the transfer layer has a single-layerstructure consisting of a protective layer or a layered structureincluding a protective layer, the protective layer contains a curedproduct of an active ray-curable resin, and an initial breakagepeeling-off force when the transfer layer is peeled under conditions ofa peeling-off temperature of 20° C. or more and 40° C. or less and apeeling-off angle of 90° is 49 N/m or less.
 2. The thermal transfersheet according to claim 1, wherein a scratch hardness (a sapphireneedle having a tip radius of 0.1 mm is used) when a face located on theside of the substrate of the transfer layer is measured by a method incompliance with JIS-K-5600-5-5 is 200 g or more.
 3. The thermal transfersheet according to claim 1, wherein a release layer directly contactingthe transfer layer is located between the substrate and the transferlayer, and a surface roughness (SRa) of a surface located on the side ofthe transfer layer of the release layer is 0.05 μm or more and 0.08 μmor less.
 4. The thermal transfer sheet according to claim 1, wherein arelease layer directly contacting the transfer layer is located betweenthe substrate and the transfer layer, the release layer contains afiller in an amount of 0.5% by mass or more and 1.5% by mass or lessbased on the total mass of the release layer, and a volume averageparticle size of the filler is 2 μm or more and 5 μm or less.
 5. Thethermal transfer sheet according to claim 1, wherein a glossiness(measurement angle: 20°) when a surface of the transfer layer aftertransferred onto a transfer receiving article is measured by a method incompliance with JIS-Z-8741 is 55% or more.
 6. The thermal transfer sheetaccording to claim 1, wherein the protective layer further comprises afirst filler having a volume average particle size of 0.1 μm or more and2 μm or less and a second filler having a volume average particle sizeof 40 nm or less.